SMITHSONIAN INST! UTION LIBRARIES AMT T AL 3 9088 00742 7453 ——<$<$== been THE DANISH INGOLF-EXPEDITION. ell 318 \ Qae VOLUME V. A 5 no./ meV Z 7. BY DROIDA (PART IL) HJALMAR BROCH. WITH 1 PLATE AND 95 FIGURES IN TEXT. COPENHAGEN. PRINTED BY BIANCO LUNO. 1918. CONTENTS Page I. Comparative anatomty of the nourishing individuals, and systematic division of the thecaphore hy. droids/ as. I Il. Thecaphore Hydroids of the Northern Atlante! ere. 6 Family series Hebellina.........+-++ 00.0 e erences 6 fearralliys ec fazer rate ye tete ieee (era yee ia interim 6 Lafea (Io aleKosicons'<)) San ocogecddon ne oo oud eorac 7 Lafea dumosa (Fleming) .......-+.-+-+--+- 7 Se pracallzma (ANGEL) i eiseae eel 9 — fruticosa M. Sars.... ..-..---1-++-+++-> 12 _Toichopoma Vevinsen.......--.+--- 21s eee eres: 15 Totchopoma obliquum (Hincks).........-..-.-- 15 Grammaria (StimpSoOm)......... 5.00.5 eee 16 Grammaria serpens (Hassall)...........+-+-+> 16 os conferta (Allman)...........- Eee 17 ME Me ricripr7u (Ma Saies) 4 soos fe esc e : 18 = immersa Nutting ........+.-+:..+- 22 Lictorella (Allman) ........-.0:20-+ 2 teeter eee 22 Lictorella pinnata (G. O. Sars)......---..----- 22 Zygophylax Quelch...........-++--s+ sees eee eee 24 Zygophylax biarmata Billard.............---.- 24 Family Campanulinid@........-.-. +20 servers 25 Subfamily Crspidellin€ ........0 1 eevee eres 26 Stegopoma LevinSen .... 2... 22. e eee eset eees 26 Stegopoma plicatile (M. Sars).......--.++++++-> 26 Cuspidella Hincks ....... 662+. eee eet ees 29 Cuspidella humilis Hincks........-0. sss seees 29 Pie ep an ie ee oee kao A nooo O Ce oa RRO eer 29 Lafoéina maxima Levy MIEN op aono sp ooo eda ue 30 Campanulina yan Beneden.........-..+++++++- 30 Campanulina turrita Hincks......... ..-++++: 31 Subfamily Calycellane ..... 1.1 ..0e eee eee ee 32 Calycella (Hincks) ...... fie. cere e eee eee 32 Calycella syringa (Linné). ...... ..-+.+++-+-> 32 Tetrapoma Levinsen......... 0-2 -e reece terres 34 Tetrapama quadridentatum (Hi Merl
  • Sener ee eee fotos -icshsusdso cdc 201 LD oi:ht: aaa ee PeMen prM pes occas Seow scoeeece 206 I. Comparative anatomy of the nourishing individuals, and systematic division of the thecaphore hydroids. As with the athecate hydroids, so also in the case of the thecaphores, the comparative anatomy of the nourishing individuals affords us a certain working basis in systematical respects. With regard to this group, however, the investigations are still somewhat incomplete, as will be seen from the following. The ectoderm of thecaphore hydroids is apparently very uniform in point of development, and the nematocysts, which in the athecates furnished good material for study, seem in the theca- phores to vary but slightly, and should on the whole be referred to the same type as in A¢hecata ilifera. This point is of some considerable interest as further confirmation of the old theory as to a closer relationship between the thecaphores and the mentioned group than between the thecaphores and A¢hecata capitata. Even among the Grammaria, where the nematocysts, in one species at any rate, are dimorphously developed, we can find no resemblance to the capsule form in A/hecata capitata. The arrangement of the stinging cells also is very uniform in the thecaphores. As a general rule, we may say that the nematocysts in the thecaphores appear in marked transverse zones about the tentacles; the only exception I have found here is that of the gigantic Bonneviella polyps, where the zonate arrangement has become effaced. A somewhat different organisation of the ectoderm is encountered in one or two families. The grown polyps of Syxtheciide and Sertulariide have developed adhesive lamella, an exterior ectodermal lamella covering the inner side of the hydrotheca for a greater or lesser extent when the polyp has withdrawn into the same. It is this ectodermal lamella which Nutting (1904 p. 10) considers as one or more “protractors”, evidently from more or less accidental breaks in the lamella, this being, in the living polyps, continuous. Nutting even goes so far as to base part of his system upon the number of “protractors”, and is here followed by Broch (1905, 1909). These protractors, however, form, as pointed out by Ktihn (1913 p. 66) an unbroken sheath or covering on the inner side of the hydro- theca, attached at its basal margin to the body of the polyp, and at the distal to the opercular appa- ratus. A similar arrangement is also found in Ayglaophenide; here likewise we encounter lamellous extensions of the ectoderm, attaching the polyp to the inner ribs of the hydrotheca. We see then, that the ectoderm itself gives us very little to go upon in a systematic classifi- cation. On the other hand, its derivates, i.e. the periderm, will in the thecaphores be found of great importance in this respect. The thecaphores are, as we know, characterised by their stiff, almost The Ingolf-Expedition. V. 7. f I HYDROIDA II bdo chitinous sheath, which is extended to form the hydrotheca. Incipient hydrotheca formation is found once or twice among the athecates, as for instance in Perigonimus, where a folding pseudo-hydrotheca surrounds the polyp below the tentacle whorl. Less attention has perhaps been paid to similar for- mations in a species such as Eudendrium vaginatum Allman, though even here we seem to find trace of an incipient hydrotheca. In the thecaphores, however, the hydrotheca has developed into a permanent component of the colony, and up to now, the systematic arrangement of the thecaphores as a whole has been based mainly upon the hydrotheca and its features. In some few families such as Halecude, Plumularide and Stliculariide, the hydrotheca is so small that the polyp cannot as a rule be withdrawn entirely into it; often, indeed, the hydrotheca seems merely to furnish a support for the basal part of the polyp. In view of the other structural conditions of the polyp, however, this must not be regarded as a purely primary feature, but should apparently in most cases be con- sidered secondary, as is shown more particularly by the two first-named families. Despite the fact that the hydrotheca in La/oézde, for instance, is far more highly developed, we must nevertheless, from the structure of the polyp, consider the last-mentioned family as representing a more primitive stage in the process of development. A point of more importance is whether the ground plan of the hydrotheca is radial or bilateral. This again is generally connected with the presence or absence of stalk. The stalked, and thus free hydrotheca, will as a rule be constructed on a radial base type, as seen in Lafoéide, Campanu- linide, and Campanulariude. ‘The more or less marked curvings of the hydrotheca, not infrequently ‘found particularly in Zafoéide, do not suffice to efface the radial base type, and even in La/foéide and Campanulinide, where the hydrotheca is sessile or even partly fused with the stolons, the radial type is distinctly perceptible. In S2/zculariid@, on the other hand, the hydrotheca is assymmetrical or bilateral, the cause of which peculiarity it is by no means easy to comprehend, since the hydrotheca is quite freely set on its stalk, which is as a rule of considerable length. This family is, however, altogether but imperfectly known up to now. The sessile hydrotheca has a greater tendency to devel- op bilaterally. In the Plumularitde, this tendency is not yet quite pronounced; we find, however, that the diaphragm in most of the species takes up an oblique position relatively to the longitudinal axis of the hydrotheca. In Aglaophentide, the development has proceeded considerably farther, the diaphragm here being either markedly oblique or else generally falling into two obliquely set portions, whereby the symmetry is arranged about a sagittal plane. This sagittal plane is often also found to be the plane of symmetry for the hydrotheca as a whole, the arrangement of the teeth at the opening being symmetrical according to the mentioned plane, while at the same time, a more or less marked lateral compression is observed in the hydrotheca. A similar bilateral development of the hydrotheca is encountered in Syntheciide and Sertulartide, where the diaphragm is as a rule also oblique, although rarely, if ever, falling so distinctly into two halves as in several of the Aglaopheniide. In Sertula- rude also, the distal parts of the hydrotheca show a distinct bilateral construction according to the same sagittal plane as in the diaphragm. A secondary formation in the hydrotheca, the closing apparatus, is likewise of considerable importance in systematic respects. In one genus of the La/oéide, Toichopoma, we find a very primitive type of closing apparatus; the lid here is simply formed by the one side of the distal end of the HYDROIDA II & hydrotheca, which is somewhat thinner than the wall of the hydrotheca generally, and can be brought in over the aperture of the hydrotheca, so as to close it. Within the family of Campanulinide, several types of lid have been developed, some consisting of the distal part of the hydrotheca (subfamily Cuspidelline) others formed by the primary roof of the hydrotheca (subfamily Cadycedline). The closing apparatus in the first case consists of folding, membranous parts, roof-shaped or conical, covering the opening of the hydrotheca. In the latter case they form a conical roof, consisting partly of folding membrane, partly of triangular plates; in this group, the closing apparatus is always sharply marked off from the hydrotheca, whereas in the Cuspidelline, it passes gradually over into the same. In Ser- tulartide also, we find several forms of closing apparatus either consisting of some few separate tri- angular plates, and thus exhibiting the same type as certain Campanulinide, or reduced to two — sometimes even a single plate — but they always appear to be formed from the original roof of the hydrotheca, in contrast to Zorchopoma and Cuspidelline. These features have been the subject of general attention in systematic respects; less considera- tion, on the other hand, has been devoted to the different structural conditions in the polyps them- selves, as arising from varying conditions in the endoderm. In Lafoéide and Campanulinide, the endoderm is, as a whole, but little differentiated; here also, however, we find an oral part above the tentacle whorl, where the indifferent cells with small nuclei are decidedly in the majority, and the structure of-the polyps here strikingly resembles that of the Bougainvilliide. In Halectiide, on the other hand, we find practically throughout, a marked distinc- tion below the tentacle whorl between a fore-stomach and the actually digesting, basal part, the sto- mach itself. While the digestive cells in the former are decidedly in the minority, it is they alone which form the endoderm of the stomach. The same differentiation into two stomach sections is still more pronounced in Plumulariide, and in the polyps of both families we must notice a ring-shaped, external constriction of the polyp, where the boundary between the two endodermal zones must be taken to lie. The same division of the endoderm of the polyp into two regions is likewise found in Ag/a- opheniide, but it is not always so easily distinguishable here on mere external observation of the polyp, being in particular frequently obscured by the ectodermal extensions previously referred to, by which the hydranth is attached to the inner ribs of the hydrotheca. ‘Even more pronounced is the differentiation of the endoderm in most of the Sythecud@e and Sertulariide. Were, the polyps are as a rule furnished with a single (ventral) blind sack placed abcaulinally to the colony. The endoderm of the stomach parts, otherwise formed by a high cylindric epithelium, forms in the blind sack only a low epithelium, which does not appear to contain digestive elements. This seems to suggest that Kiihn’s supposition (1913 p. 68) is correct, and that the abcaul- ine blind sack in these families serves for storage of nutritive matter to be digested subsequently, when the polyp is again in a resting position. The abcauline blind sack must be said to be characteristic of the two families, even though in primitive forms such as for instance 7hyroscyphus and Dynamena, only an indication of it may be found. Finally, there is yet another type of polyp found in Campanulariide and Silicularude. While all the remaining families of thecaphores are characterised by a conical peristome, this is, in the _two mentioned families, clubshaped, situate with a narrow base above the tentacle whorl on the broad 1* 4 HYDROIDA II body of the polyp. In external habitus, the polyps of these families thus markedly resemble those of Eudendriude, and the similarity in point of internal structure is equally remarkable. The endoderm of the peristome, or the proboscis, is quite predominantly composed of indifferent cells, while the gastral part has a fairly homogeneous endodermal covering of digestive cells. Owing to the devia- tion of the polyps in external habitus, I have in a former work, (1909 p. 133) marked off these two families as a separate sub-order, Prodoscoidea. Considering the mentioned features of organisation, however, in the light of what has been stated above, it will hardly be correct to retain this sub- order; but it forms a special family series, ranking with the others, where the thecaphores as a whole must be said to fall, as will be further referred to in the following. A much disputed group is formed by the genus Bonneviella, which I formerly (1909 a) noted off as a separate family. Kithn (1913 p. 252) inclines to the view that the genus must be referred to Lafoéide, whereas Nutting, in his latest work (1915 p. 94) retains the family of Bonneviellide. Such description as has been given of the anatomical conditions in this species is as a matter of fact not sufficient fully to elucidate the relationship of the group, and Nutting’s explanation, in which he considers that my previous observations may be confirmed, still lacks the essential point required; to wit, the development of the so-called “veloid”’. A comparison with the remaining genera has led me rather to incline towards Kiihn’s theory, that the formation in question can hardly be regarded as altogether ectodermal, the inner layer being probably rather an extreme development of the indiffe- rent cells of the endoderm. If this supposition prove correct — a point which can only be determined by study of the development of the polyps — the position of the genus will nevertheless still be doubtful; most of the facts would then seem to lead towards their inclusion as a high form of devel- opment of Campanulariide; we may, however, also with good reason suppose the origin to be in Lafoéide. Having no suitable material for further study of these questions available, I do not pur- pose here to enter upon further theoretical discussion as to the systematic position of the genus. I would merely point out once more, that the interpretation of the peristome as an ectodermal gullet is doubtful in the highest degree. On summing up the above anatomical data, we find that the thecaphore hydroids fall into four main groups or series of families, which are of great interest from a phylogenetic point of view. The most primitive family series is that of //ede//ina, with its conical proboscis and with homogeneous gastral endoderm. This group, which embraces the families Zafoéide, and Campanulinide, exhibits a marked affinity with the athecate family of Bougarnvilliide, and probably originated from the same. From //ebellina again, two new family series are derived, viz: on the one hand that of Hale- cuima, with the families Haleciide, Plumulariide, and Aglaopheniide, and on the other, the series Sev- tulartuma, with the families of Syztheciide and Sertulariide. Haleciina is characterised by its bipartite gastral portion, which is divided into a fore-stomach (probably non-digesting) and a digestive basal part. This division is, especially in certain primitive /Za/eciwm species, still but slightly pronounced, thus giving the transition from Hedellina. In Sertulariidae, on the other hand, the basal, one-sided blind sack is developed as a storage chamber; the transition from /eée//ina is here represented by forms such as Thyroscyphus, where the partition of the gastral parts into the divisions named is still barely indicated. An exceptional position is that of the Prodboscotda series, with club-shaped proboscis. The HYDROIDA II 5 group may be supposed to originate from Hededlina; there is, however, much which would seem to suggest closer relationship with Lwdendride. I have in a previous work (1909 p. 132) drawn atten- tion to several features pointing in this direction; Kiihn, (1913 p. 246) endeavours to disprove the close resemblance, while on the other hand Nutting, (1915 p. 20) notes further similarities, and, like Stechow, (1913 p. 22) comes to the conclusion that a close relationship between Prodoscorda and Eudendriide is not to be denied. I would here merely mention one point, which Kiihn regards as of great importance, but which Nutting has not subjected to closer consideration. Kiithn finds that there is a difference of principle in the gonosomes. In this connection, several of the gonangia of the Campanulariide will be found of considerable interest. In the athecates, we repeatedly find that single gonophores, as in Aougainvillea, Hydractinia, and Eudendrium, collect on the stalks of some few hydranths; in several species moreover, we find a reduction of the terminal polyp, so that the whole of the gonophoriferous complex is here transformed into a blastostyle. As a matter of fact, we have in such cases to deal with gonangia aggregates, differing only in gonotheca formation from the gono- some in species such as for instance Laomedea flexuosa. The development of the gonangia here shows us a reduced terminal polyp, which has now formed an “Endplatte”, on the stalks of which gonophores appear. If at the same time we imagine that the gonophores do not penetrate the peri- sarc, but that the latter expands instead into a protecting sheath, we have then the gonotheca in its typical form for Campanulariide. It may also be imagined as arising by formation of gonophores on the basal parts of the hydranth, within the hydrotheca, when, on the one hand, the hydranth will thereby be reduced to an “Endplatte”, while on the other hand, hypertrophy of the hydrotheca will set in. Either of these alternatives may be considered as the possible starting point. I do not insist that this explanation of the origin of the gonosome in the group is the correct one; there is, however, nothing to disprove it in the results of investigations made up to date, and it will, if confirmed, alto- gether disprove the existence of a difference of principle in the gonosomes, as maintained by Kithn. This proof is thus likewise inadmissible as finally disposing of the supposition of a closer relationship between Proboscotda and Eudendrude. If we now endeavour, as in the case of the athecates, to summarise the elucidated features and previous views in a key for determination, we must at the outset point out that in this instance such a method cannot so easily be employed without reserve, as the transitions in the thecaphores are more gradual than in the athecates. An endeavour may nevertheless be made to draw up a scheme of the nature indicated. I. Polyps with conical, pointed oral part. A. The gastral endoderm uniformly developed; polyps and hydrothece constructed according to a radially symmetric ground plan. (Family series Hebellina). I. Hydrothecee without opercula or with a primitive closing apparatus formed from the thinner distal part of one side of the hydrotheca. Family Lafoéide. II. Hydrothecz with roof-shaped or conical opercula of composite structure. Family Campanulinide B. Gastral endoderm differentiated in heterogeneous parts. I. Polyps with fore-stomach and digestive basal stomach parts. (Family series Haleciina). 6 HYDROIDA II a. Hydrothecee small, radially symmetrical, cannot accommodate the contracted hydranth. Fa- mily //alecide. b. Bilaterally symmetrical hydrothece, with obliquely set diaphragm. x. Diaphragm simple. Hydrothecz small, approximately radial structure, generally without teeth; rudimentary or stalked and mobile, two-chambered sarcotheca. Family Plumulariide. xx. Diaphragm generally composed of two obliquely set portions; hydrothece markedly bilateral, large, most frequently toothed. Sarcothece all or some one-chambered, sessile and immobile. Family Avlaopheniide. II. Polyps with a basally situate, ventral blind sack with low endoderm cells. Hydrothece gene- rally bilateral. (Family series Sertulariina). a. Hydrothecze without opercula. Family Syxthecide. b. Hydrothecee with opercular apparatus. Family Sertulariide. 2. Polyps with club-shaped or trumpet-shaped oral parts. (Family series Proboscoida). A. Hydrothece large, radially symmetrical. Family Campanularitde. B. Hydrothecze small, thick-walled, and bilaterally symmetrical. Family S7liculariide. Il. Thecaphore Hydroids of the Northern Atlantic. Family series Hebellina nov. Family Lafoéide. Hydrothece deep bell- to tube-shaped, radially symmetrical after their ground plan, stalked or sessile, at times partly fused with the mother tube; diaphragma rarely present. ‘The hydrothecze without opercula; exceptionally, the distal end of the one wall in the hydrotheca may fold in over the aperture. The colonies are stolonial or sympodial. The polyps are radially symmetrical, with conically pointed oral part; the endoderm is divided into an oral and a gastral part; the gastral endoderm is homogeneous. The structure of the polyps gives this family a primitive rank among the thecaphores, and among its lowest genera //ebel/a must be counted as taking a typical position; this genus is, how- ever, especially distributed in the warmer seas. The genus has also been recorded from northern waters, although evidently erroneously; its only northern representative should be Hebella pocillum (Hincks) but as it lacks the diaphragm, it cannot be allowed to remain in this genus, and its identity will be dealt with later on. In course of time, a whole series has been set up with genera of La/foéide@, and on going through the list compiled by Stechow (1913 p. 44) we find that considerable weight is attached to the accumulation of the gonangia in aggregates (scapus, coppinia) or their appearing singly. I have recently (1917) in studying the coppinia of Grammaria abietina, set forth what we know up to the HYDROIDA II “I present concerning this distinguishing feature; our knowledge is, in reality, so insufficient that the greatest care should be exercised in answering for species even where this character has been noted, after superficial study, as the only point of difference in comparison with the nearest related species. It is clear, that in certain species, the gonothecee of the one sex (the female) appear aggregated as scapus or coppinia, while those of the other sex (the male) occur singly. Even though we may not at present possess definite proof, it is nevertheless highly probable that also certain Lafoéide may have unisexual colonies; in such case, however, the occurrence of the gonothece singly or in aggregates will even fail us as a specific character. Obviously then, in the present imperfect state of our know- ledge as to the gonangia of the different species, the feature in question must be discarded altogether as a generic character. Until we know more about the matter, it will certainly be most correct to disregard the question of gonangia entirely when drawing the limitations of the various genera. Gen. Lafoéa (Lamouroux). The colony consisting of upright rhizocaulome formations, or creeping, with tubular or narrow bell-shaped hydrothecee. The hydrothecze are without diaphragma or opercular apparatus, stalked or sessile, in the latter case separated from the stolon by a more or less marked constriction; where the hydrotheca lies adjoining the stolons, it is possible to distinguish between the wall of the hydrotheca and that of the stolon. A whole series of species belonging to this genus have been described from the northern seas, and many of them are based on the distinction as to whether the colonies are creeping or upright, a character which, as we find on closer investigation, can only be applied with the greatest caution. It has long been recognised that Zafoéa dumosa may either occur as a creeping form, or may form upright rhizocaulome colonies; this fact in itself should be sufficient to point the necessity of careful consideration, and a closer study of the northern species reveals the fact that one and the same spe- cies may at times occur creeping, at others form upright colonies, when some few stolons emancipate themselves from the underlayer and thus form a suitable substratum over which other stolons may creep. Another feature in the Ze/oéa species which renders their limitation exceptionally difficult is their extrordinary power of variation. Such variation is evidently due in part to the influence of physical conditions in their environment, which have led to the formation of gigantic arctic forms, or heavily built, robust cold-water forms. Critical study of the very extensive material available has thus ed to considerable reduction in the number of species. Lafoéa dumosa (Fleming) L. Agassiz. 1828 Campanularia dumosa, Fleming, A History of British Animals, p. 548. 1860 Lafoea dumosa, 1, Agassiz, Contributions to the Natural History of the United States, p. 351. Colonies creeping or upright, irregularly branched and stiffly built rhizocaulome formations. _ Hydrothecee developed slightly asymmetrically, tubular, with slightly outward curving margin; they HYDROIDA II (o0) are separated by a constriction from the stolons, or may, more rarely, exhibit an indication of stalk, forming half a spiral whorl. The gonangia are collected in coppiniz with tubes much twisted. The coppiniz are herma- phroditic, with the male gonothecee wedged in among the female. Material: ‘Ingolf’ St. 6, 63°43’ N., 14°34’ W.; depth go fathoms, 7.0% — = (86; 65°03;67 IN. 23°47.6) We (== 76 — (West-Iceland) — = 07 (05:02)2'N 230c6.20 Wasi -— (West-Iceland) “Nor? 63°30 N. 20°r4' W.; — 80 metres Greenland: Sukkertoppen (on Bo/¢enia) (no further data) Iceland: Vestmann6é depth 28 fathoms — Skjalfandi Bay depth 28 fathoms The Faroe Islands: 62°29' N., 7°37' W.; depth 110 metres, 871° — — 627116 Ni/6°06), Wee) sr T00 — — 7 miles N. by E. of Myggenes point; depth 57 fathoms — _ 6 — N. by W. of Store Kalsé; — 60 — ~ — Deep hole at north point of Nolsd; — 100 — — = Borones N. 75 W. — 300 — 200 m. miwim a = ow 000M. tame 1000 M. ddustistecseemeniesenial OO ONITs Fig. I. The Distribution of Zafoéw dumosa in the Northern Atlantic. In the hatched regions the literature notes a common occurrence. HYDROIDA II 9 Some writers unite this species with the two following; this is, however, as I have previously shown (1908 p. 33) not correct. Both in its creeping form and in the upright colonies it is very typi- cally distinct from the remaining northern Za/oéa species, partly by its very slightly asymmetrical hydrothecze, which have practically no real stalk at all, partly by the fact that the hydrothece, which are set very far apart, form almost a right angle with their corresponding stolon. The species is widely distributed in the northern seas (Fig.I). It is a distinctly boreai species, which can, however, penetrate far into southern waters, and has been recorded, for instance, from the Mediterranean (Babi¢ i1g1o p. 213). On the other hand, purely arctic conditions seem quickly to set a limit to its progress. Lafoéa gracillima (Alder) Hincks. 1856 Campanularia gracillima, Alder, A notice of some new genera and species, p. 361, pl. 14 figs. 5—6. 1874 Lafoéa gracillima, Hincks, Notes on Norwegian Hydroids from deep-water, p. 132. 1868 Lafoéa pygmea pars, Hincks, A History of the British Hydroid Zoophytes, p. 205, pl. 40 fig. 3. 1887 Lafoéa fruticosa pars, Bergh, Goplepolyper (Hydroider) fra Karahavet, p. 334. The colony is creeping or upright, with irregularly branched rhizocaulome formation. The hydrothecee are narrow, tubular, curved, with the convex side turned upwards; the opening margin is on the concave (lower) side never curved outwards, but may be slightly so on the convex side of the hydrotheca. The hydrotheca passes gradually over into the stalk, which is of varying length, and with a spiral coil closer in some, more open in others. In upright colonies, the stalk axis forms as a rule a very acute angle with that of the mother tube, the basal part of the hydrotheca is often nearly parallel with the latter. The gonothecze are compressed in hermaphroditic coppiniz, the long tubes of which are as a rule highly curved. The male gonothecee occur wedged in between the female. Forma ¢yfica: finely built colonies, with hydrothece set wide apart; the hydrothece entirely tube-shaped, with loosely spiral stalk, as a rule with two turns. Forma e/egantula: colonies of coarser build, with closely set hydrothecee; the hydrothecz often with the upper part of the opening margin curved slightly outwards; stalk with a varying number of mostly close-spiral windings. Material: Forma ¢yfica: “Ingolf’ St. 1,. 62°30’ N., 8°21’ W., depth 132 fathoms 7,2° — - 55, 63°33’ N., 15°02 W, — 316 — _ = 5,9° > Gy (Gehan ING wate \iG — 170 = — -— = S87 0502.07 NE 1 23550.27W., — 110 -- -- -- > OG) Wau ING, storsyey \Vey — 752 — = 2,1° — = P1270 007334) IN. 20:05) W., — 44 — 5,6° Iceland: Skagestrand — 44 — 9 miles N.74E. of Hornet, east coast of Iceland, depth 38 fathoms 62°17’ N., 4°57’ W., depth 144 fathoms. The Ingolf-Expedition. V. 7. 2 10 HYDROIDA II Forma elegantula: “Ingolf”? St. 3, 63°35’ N., 10°24’ W., depth 272 fathoms, 0,5° -- - 29, 65°34’ N., 54°31’ W., — 68 0,2° — - 31, 66°35’ N, 55°54, W., — 88 _ 1,6° — - 33, 67°57’ N., 55°30 W., — 35 — 0.8° 0 = BAN OST ING. 54°87 Woe ee 55) = Greenland: Davis Strait (precise locality not stated) depth 100 fathoms. Akudlek (no further data) Egedesminde (- — — ) Mouth of Ameralikfjord = ( - — —) Sukkertoppen, on Bolfenza (- — —) Jakobshavn (- — —) Hurry Inlet, depth o—7 fathoms (East Greenland Expedition) Bae ae oe ee a: a ge) Harry Land — 20 ( - -— ) Iceland: “Thor” 52 miles E. of Langanes Skjalfandi Bay, depth 28 fathoms g miles N.74E. of Hornet, east coast of Iceland, depth 38 fathoms 64°17,5' N., 14°44’ W., depth 4o fathoms, 5,12° The Faroe Islands: 61°40' N., 7°40’ W., — 135 _—. 6 miles N. by W. of Store Kals6, depth 60 fathoms Kara Sea “Dijmphna” (labelled Lafoéa fruticosa). The distinguishing features between Lafoéa gracillima and Lafoéa fruticosa may often appear very insignificant, and in arctic waters especially one may often be in doubt as to whether a specimen is a robustly built colony of Z. gvacillima forma elegantula or a finely built Z. fruticosa forma genuina. The feature emphasised by Bonnevie (1899 p. 61) viz: the number of spiral turns on the stalk, is in particular extremely variable in somewhat larger colonies, and it is likewise found that the angle between stalk and mother stolon, especially among creeping colonies, is little to be relied on. Another feature, however, to which I have long since drawn attention (1907 p. 7) seems to be more constant, and will also according to the present material serve to determine the identity of species. The feature in question consists in the fact that the abcauline concave side of the hydrotheca in -Lafoéa gracil- lima lacks the basal convexity found in ZLafoéa fruticosa, and that the margin of the hydrotheca on this side is never curved outwards in La/oéa gracillima, in contrast to Lafoéa fruticosa, where the lower (concave) side of the hydrotheca is thus always more or less S-shaped in profile. Among the synonyms for Lafoéa gracillima we have also here included Lafoéa pygmea pars. Jaderholm (1909 p. 80) includes this species as a synonym under Calycella syringa, and he is un- doubtedly right in so doing. According to Hincks (1868 p. 205) the original drawings by Alder exhibit indications of opercular formation in the hydrotheca here and there, a point which beyond question suggests this species. On the other hand, Hincks’s description is entirely in agreement with the HYDROIDA II Il creeping colonies of La/foéa gracillima, and a number of colonies which have later been identified as Lafoéa pygme@a should doubtless be referred to Lafoéa gracillima. Bonnevie, (1899 p. 62) notes in her table as to the hydrothece that they have “slightly outward-curving margin”; this does not agree with Hincks’s expression “hydrothece .. . cylindrical, elongate and narrow” or with his drawing of the species. In my first report on the hydroids from “Michael Sars” (1903 the table) I recorded La/oéa pygmea from several localities, giving also a drawing of the coppinia of the species; subsequent revi- sion of the material has shown me that the specimen indicated is, like most of the others, a typical, creeping La/oéa gracillima, while some few colonies are creeping Lafoéa dumosa. Lafoéa pygmea must . 200m. SeonecoQOGih ceetnooses tooo m. erat a COONTE: Fig. II. Localities of Zafoéa gracillima forma typica @ and forma elegantula + in the northern Atlantic. y In the hatched regions the literature denotes a common occurrence of the species. (The dates from British seas are incomplete on account of a general confusion with Lafoéa fruticosa). thus mainly be regarded as synonymous with Za/foéa gracillima and Calycella syringa, and can accor- dingly no longer be counted as an independent species. Lafoéa gracillima appears in two forms, affording parallels to those of the following species. The finely built forma ¢yfica is quite cosmopolitan in its occurrence, and has been met with in all seas from pole to pole. In arctic — and as far as can be seen also antarctic — waters, there has also developed, in addition to forma ¢ypzca, a more robust and closely built forma e/egantwla, the stalk of which generally commences with a single loose winding, continuing then in a varying number of close turns. Forma e/egantula is, as mentioned, arctic, but may (text fig. II) also at times penetrate into boreal waters. 12 HYDROIDA II Lafoéa fruticosa M. Sars. 1851 Campanularia fruticosa, M. Sars, Beretning om en i Sommeren 1849 foretagen zoologisk Reise, pi 13r, 138: 1863 Lafoéa fruticosa, M. Sars, Bemzerkninger over fire norske Hydroider, p. 30. 1868 — focillum, Hincks, A History of the British Hydroid Zoophytes, p. 204, pl. 40, fig. 2. 1874 — grandis, Hincks, On deep-water Hydroida from Iceland, p. 147, pl. 6, figs. 1—2. 1899 — symmetrica, Bonnevie, Norske Nordhavs-Expedition, p. 64, pl. V, figs. 2. and 4. The colonies are creeping, or form upright, irregular rhizocaulomes. The hydrothece are cylin- drical or narrowly bell-shaped, more or less asymmetrically developed or slightly curved, the one side as a rule curving somewhat more markedly outwards than the other. The hydrothece have as a rule a slightly expanded basal part and a more or less outward curving opening margin, they are sharply marked off from the stalk, which is of varying length, spirally turned, or less frequently divided into rings. The stalk itself forms, in the upright colonies, an open angle of 45°—80° with the mother tube. The gonothecee are gathered in hermaphroditic coppiniz, the tubes of which are as a rule highly curved. The male gonothecee are wedged in among the female. Forma genuzna: finely built colonies, always with asymmetrical, narrow hydrothece, the stalk forming an acute angle with the mother tube. Forma grandis: coarsely built colonies with wide cylindrical to narrowly bell-shaped hydrothecz; hy- drothece often almost or entirely symmetrical, the stalk generally forming a more obtuse angle with the mother tube. Material: Forma genuina: “Ingolf St. 34 65°17’ N. 54°17’ W., depth 55 fathoms — - 86 65°03,6' N. 23°47,6' W., — 76 — -- = 87) 65202;37 Ni, 23256,2) Ws — 0 — “Thor” 6595200 Ne 235000 a Wes ~~ 62 metres = 61°07’ N., 9°30’ W., —- 835 — Greenland: Egedesminde (no details noted) Proven (- --- — ) Cape Tobin, depth 57 fathoms (East Greenland Expedition) Mouth of Hurry Inlet, — so — ( — — — ) Iceland: Skjalfandi Bay, depth 28 fathoms 9 miles N.74 E. of Hornet, east coast of Iceland, — 38 — The Faroe Islands: 7 miles N. by E. of Myggenees, —- J — Forma grandis: “Ingolf” St. 2 63°04’ N., 9°22’ W., depth 262 fathoms 5,3° — = 4) 640072 Nive TL gt20 Wey — 237-0 — 255° = er BANS Sy SIN. SAL: Mie S50 oe = — - 95 65°14’ N. 30°39’ W,, — 7752 — 2,1 HYDROIDA II 13 Greenland: Egedesminde, depth 30—4o fathoms Sukkertoppen, on oltenza (no details noted) Ingmikertok, Angmagsalikfjord (depth not given) (East-Greenland Expedition) Iceland: 33 miles SE. '/, E. of Stokkesnzs near Hornsvig, depth 84 fathoms (labelled Za/oéa Jruticosa). We have here a species of highly variable character, especially in the northern waters, where the biophysical factors evidently exercise an important and determinative influence upon the variation of the species. There is consequently also much confusion as to the synonymy of the species. La/oéa Jruticosa was established by M. Sars (1849) and in his description we find the following with regard to the hydrothecze: “superne latioribus, inferne coarctatis”. This certainly gives the impression of a hydrotheca having its lower portion, partly on account of the curvature of the wall, broader than the upper, which again expands nearer the opening. The same is also seen in the drawing subsequently given by G. O. Sars (1873 Tab. IV, figs. 17—18) of the species, undoubtedly based upon M. Sars’s type specimens. This does not agree with the statements of Bonnevie (1899 p. 65) and we can hardly help feeling that among Bonnevie’s Lafoéa fruticosa there must also be some colonies of Lafoéa gracillima forma elegantula; a supposition which is, moreover, confirmed by the study of her material in Christiania. On the other hand, Bonnevie has (l.c.) established an entirely new species, Lafoéta symmetrica, which as a matter of fact is based upon variants of La/oéa fruticosa. The principal difference between Lafoéa fruticosa and Lafoéa symmetrica is, according to Bonnevie, the fact that the latter species has symmetrical hydrothecz, whereas these are of asymmetrical structure in the former. It will be seen, however, from the drawings of hydrothecze given (1899 Tab. V, fig. 2c’) that asymmetrical hydrothecee can also occur in Lafoéa symmetrica. On the other hand, further examina- tion of the hydrothecz in Le/foéa fruticosa (cf. Br och 1908 fig. 4, 1909 textfig. 19) shows that the asymmetry is often but very slightly pronounced, and even disappears altogether in a greater or lesser percen- tage of the hydrothece in a fairly large colony. We find, in other words, that in this respect, every imaginable transition form may be met with from La/foéa fruticosa to Lafoéa symmetrica; the character in question is therefore not suitable for purposes of specific distinction. There remains then, the size, which is said to differ as between La/oéa fruticosa, L. symmetrica, and L. grandis. It is soon found, however, that this character likewise is here unserviceable. On the one hand, the three species form, according to Bonnevie, a finite series of sizes, Lafoéa symmetrica being from the drawings and de- scription, larger than La/oéa fruticosa, but smaller than La/foéa grandis. On the other hand, a large material of the three forms reveals the fact there is no discernible interval throughout the series; all intermediate stages are found, from finely built colonies of La/oéa fruticosa to such extreme cold-water variants as those upon which Hincks’s ZLafoéa grandis is based. We are thus compelled to include the forms under one species, the correct name of which should be La/oéa fruticosa. The amalgamation of these three species into one, however, involves the further abolition of Lafoéa pocillum Hincks (1868 p. 204, pl. XL, fig. 2). The shape of the hydrothece is very correctly described by Hincks as follows: “tumid below, with the sides curved inwards above, and expanding again slightly towards the top”. This coincides entirely with M. Sars’s “superne latioribus, inferne -coarctatis”. The length of the stalk in Lafoéa species and its spiral winding or division into separate 14 HYDROIDA II rings varies even within a single large colony to such a degree that the features in question cannot be taken as distinctive specific characters, unless combined with others more sound. There remains then the creeping form of colony. But La/oéa fruticosa here differs in no wise from the remaining species of the genus; its colonies may be pure upright rhizocaulome formations, but this is very rarely the case. Generally, the somewhat larger colonies consist partly of upright, partly of creeping por- tions, and it is very common to meet with such composite colonies, when they are brought up with the underlayer attached. Exclusively creeping colonies thus merely form the other extreme in the PYCa oe me ES a oe (OO Se 1000 m, bees wasetee orients 2 OOM: Fig. III. The distribution of Lafoéa fruticosa forma genuina @ and forma grandis + in the northern Atlantic. The hatched region denotes a common occurrence of Lafoéa fruticosa according to literature. (In British waters the dates are to be revised owing to confusion of the species with Zafoéa gracillima). same series of variants. Consequently therefore, Zafoéa pocillum must be discarded, as being synony- mous with Lafoéa fruticosa. Jaderholm (1909 p. 71) follows, stating no particular reason, the example of Nutting (1901 p. 175} and ascribes Za/oéa pocillum to the genus /edella. Nutting, in his diagnosis of this genus, states as follows: “Hydrothece ... having their cavities separated from those of the stem by a partial septum”. Such septum or diaphragm is altogether lacking in the European specimens of La/oéa pocillum. It must not be forgotten, however, that the former species partly owe their existence to external determining factors. Disregarding the creeping form of colony as opposed to the upright, the differ- ences presented by the colonies in a less extensive material are considerable enough to warrant at any rate temporary distinction of species, and it would in these cases be incorrect not to notice the HYDROIDA II 15 same. Such “species” will on further investigation often be found to represent regular groups of vari- ants. And this is precisely the case here. In La/oéa fruticosa, the transition forms are not infrequent in boreal waters, and it may often appear doubtful where the limits should be drawn. It is perfectly admissible, in the case of La/oéa /ruticosa, to distinguish between a forma genxwina as opposed to forma grandis, the first-nuamed comprising that group of variants hitherto indicated as La/oéa /ruticosa, and the latter embracing the species La/oéa grandis and Lafoéa symmetrica. The two forms also make typical geographical groups. Forma genuina, which must be regarded as the mother form, is of very wide distribution; it is encountered together with the following form (text fig. III) in the arctic region, and alone in boreal and southern waters, both in the Atlantic and the Pacific, where it has been met with so far down as Hawaii. Intermediate forms are, as mentioned, frequently found in boreal and arctic waters, more particularly in the transition zones between the two. Forma grandis is of strictly arctic occurrence, and must here be regarded as a typical character form. Billard’s record (1907 p. 176) of a find at Cape Spartel must, from the measurements and figures given, be due to incorrect diagnosis. Gen. Toichopoma Levinsen. The colonies are creeping, or form upright, irregularly branched rhizocaulomes, with stalked, cylindrical hydrothecee. The hydrothecee lack the diaphragm, but have a primitive closing apparatus; the distal integral part of one side of the hydrotheca wall can be closed down over the aperture. Toichopoma obliquum (Hincks) Levinsen. 1874 Calycella obligua, Hincks, On deep-water Hydroida from Iceland, p. 149, pl. 6, figs. 4—5. 1893 Zoichopoma obliguum, Levinsen, Meduser, Ctenophorer og Hydroider, p. 178. IQII — — Kramp, Report on the Hydroids, p. 374, pl. XX, fig. 4, pl. XXIII, figs. 5—8, pl. XXIV, fig. 1. The colonies are creeping, or form upright irregularly branched rhizocaulomes. The hydrothecz have a, short stalk with a varying number of spiral windings; they are cylindrical, curved, with an adcauline convexity, as a rule somewhat expanded near the base, and slightly broader again near the aperture, which in open hydrothecee is somewhat asymmetrical; the hydrotheca passes gradually over into the stalk. The abcauline distal part of the aperture is thin, and can be closed in towards the opposite wall over the contracted polyp. The gonothecze are closely packed in a (hermaphroditic?) coppinia on stem or branches; the single gonothece are pentagonal or hexagonal, with a short, narrow cylindrical neck. Between the gonothecee are inserted long, highly curved tubes, forming a close network over the coppinia. Material: Greenland: Jakobshavn (no details noted) Egedesminde ( - — — ) Toichopoma obliqguum is a high arctic species, recorded both from West and East Greenland, as well as from Spitzbergen and the Murman Sea. 16 HYDROIDA II Gen. Grammaria (Stimpson). Colonies creeping or forming upright, irregularly branched rhizocaulomes with sessile, cylin- drical hydrothecee, which are to a varying extent fused with the tubes, so that in this part it is im- possible to distinguish between the wall of the hydrotheca and tube. The hydrothece can at times exhibit a basal constriction forming a boundary between them and the mother tube, but such con- striction may also often be wanting. Diaphragm and operculum lacking. In earlier works, the creeping species have been incorrectly noted as a separate genus, /7/ed/um. The type of this genus was /7lellum serpens (Hassall). I have previously (1912 p. 10) pointed out that this species should be classed under Gvammaria, and am supported here by Kramp (1914 p. 1030). Further proof is afforded by Stechow, who describes (1913 p. 118) a species Grammaria scandens, with both creeping and upright colonies; it would seem doubtful whether this species should properly be maintained beside Grammaria abietina, which may often be found in Throndhjem Fjord in the same manner. Stechow (l. c. p. 121) considers, however, that the genera should be maintained, “da ihre Beibehaltung eine grosse Bequemlichkeit ftir die Bestimmung ist”. Grammaria serpens (Hassall) Broch. 1848 Campanularia serpens, Hassall, Catalogue of Irish Zoophytes, p. 2223. 1868 /ilellum serpens, Hincks, A History of the British Hydroid Zoophytes, p. 150. 1912 Grammaria serpens, Broch, Hydroida from the “Michael Sars”, p. Io. Colonies creeping. Hydrothecee cylindrical, bent to an angle, the basal part fused with the stolon. The hydrotheca is tubular, quite cylindrical, or with slightly outward curving opening margin; the transition to the stolon is as a rule marked by a slight constriction. The gonothecze are collected in close coppiniz, with highly curved tubes. They are herma- phroditic, with the male gonothecee wedged in between the female. Material: “Ingolf”’ St. 87 65°02,3' N.. 22°56,2’ W., depth 110 fathoms “hor? 64°16' N. 22°17) W, — 50 metres — 64°02’ N., 22°33 W. — 34. _- 63°30’ N. 20°14’ W. — 80 — Greenland: Egedesminde (without further details) Store Hellefiskebanke ( — -- — ) Davis Strait ( — aa — ) Iceland: Vadlevik, depth 80 fathoms 33 miles SE. of Stokkesnzs near Hornvig — 84 _ g'/, — S. by W. #/, W. of Ingolfshofdi, depth not given The Faroe Islands: 8—1o0 miles N. of the Faroe Islands (without further details) 7 miles N. by E. of Myggenzes point, depth 57 fathoms HYDROIDA II 17 6 miles N. by W. of Store Kals6 depth 60 fathoms Deep hole at north point of Nolso — 100 — Borénees 13/, miles in N. 75 W., — 30 — 5 miles SSE. of Bispen — 5 — 13 — W. by S. of Munken — 150 — Stokken 2 miles in 5. 22 E. —- 5 — This remarkable species was formerly considered as the type of the genus /ie//dwm. Bonne- vie (1899) notes it under Zafoéa, but it should, as I have indicated above, be classed under the genus meme eee, focom. oom oe meeemee mee, 2000 M1. Fig. IV. The occurrence of Grammaria serfens in the Northern Atlantic. ' In the hatched regions the literature notes a common occurrence. Grammaria. From the records, the species is of highly cosmopolitan distribution; it is less numerous, however, in the arctic seas, and is likewise not altogether of common occurrence in warmer waters. It is most frequently met with in the mid-littoral parts of the boreal region (fig. IV) and is here but rarely found at greater depths. Grammaria conferta (Allman) Broch. 1877 Cryplolaria conferta, Allman, Report on the Hydroida.... of the Gulf Stream, p. 17, pl. 12, figs. 6—Io. 1912 Grammaria conferta, Broch, Hydroida from the “Michael Sars”, p. 10. Upright, irregularly branched rhizocaulomes, the outer ramifications monosiphonic, the basal The Ingolf-Expedition. V. 7. 3 18 HYDROIDA II parts polysiphonic. The hydrothece are arranged on the branches and stem in two opposite rows, alternating, with the mouth turned now to one side, now to the other. The hydrothecz are large, tubular, passing by a slightly marked constriction over into the stolon; the diaphragm is lacking. In its proximal part, the hydrotheca is fused with the stolon; owing to a sharp bend in the hydrotheca, the distal part is almost perpendicular to the proximal. Opening margin slightly everted. The gonothece are set close together in a (hermaphroditic?) scapus (without inserted tubes) on the branches or stem. The gonothecze are bottle-shaped, with a short neck. Material: “Ingolf St. 11 64°34' N., 31°12’ W., depth 1300 fathoms _1,6° — = 3h 160735 N3) 55¢447 W. — 88 _ ThOn — - 32 66°35’ N., 56°38’ W., — 318 — 3,9° ==) = 178) G0°3 7) ON.) 927-52, We, a W990 = 4)5° = - 92 64°44 N., 32°52’ W., _ 976 — 1,4° In a previous work (1912 p. 10) it was pointed out that Cryffolaria conferta is distinguished from the remaining Grammaria species only by differences so slight that they do not by any means warrant generic separation; the bilateral arrangement of the hydrothece is not an adequate generic character. — Interesting from a biological point of view is the fact that this typical deep-sea form as a rule developes filiform, root-like basal offshoots, for attachment to the soft bottom; I have, however, once seen a colony which had attached itself to a fragment of the shell of a deep-water mollusc, and had in consequence less highly developed offshoots than most colonies otherwise have. Grammaria confertas northern limit of occurrence is moved a considerable distance farther north by the latest finds; otherwise, its distribution is that of a typically abyssal form, and the record of its occurrence in only 88 fathoms’ depth far up in Danmark Strait thus comes as a surprise; the more so since the species should generally be noted as a character form for the warmer and deeper waters of the Atlantic. It does not penetrate in over the submarine ridges which form the southern boundary of the Norwegian Sea. Grammaria abietina (M. Sars) Stimpson. 1851 Campanularia abietina, M. Sars, Beretning om en i Sommeren 1849 foretagen Zoologisk Reise, p. 131. 1854 Grammaria robusta, Stimpson, Synopsis of the Marine Invertebrata of Grand Manan, p. 9, pl. 1, fig, 3: The colonies form coarsely built, stiff, irregularly branched rhizocaulomes, in exceptional cases with creeping portions. The hydrothecee lack the diaphragm, and pass over without constriction into the mother tube; their lower limit is formed by the ring of small chitinous bodies to which the base of the hydranth is attached. The hydrothecze are tubular, bent to an angle, and have as a rule a slightly everted opening margin. The plane of the aperture itself is normally parallel with the axis of the branch; in forms with particularly short hydrothecz, the aperture is slightly turned upwards. The hydrothecze project in most cases far beyond the secondary tubes. The gonothece are closely collected in hermaphroditic coppiniee with highly curved tubes. The HYDROIDA II 19 female gonothecze are much compressed, sessile; the male are stalked, with the stalks pressed in among the female gonothece. There are only a small number of almost spherical male gonothece in the coppinia; they are freely placed between the surface of the female aggregate and the outer coils of the tubes. The female gonophores are heteromedusoids; the male reduced cryptomedusoids; the fertile colony has nematocysts dimorphously developed. Forma ¢ypica: The upper (adcauline) wall of the hydrotheca projects 1,5—3 times the diameter of the aperture beyond the tubes; the plane of the aperture is parallel with the axis of the branch. Forma brevicyatha: the free portion of the adcauline wall is 0,5—1 times the diameter of the aperture; the aperture itself is turned obliquely upward. Material: Forma ¢yfica: “Ingolf St. 34 65°17’ N., 54°17’ W., depth 55 fathoms _ = Se OP GY ING, ae W,, — 68 — 7,32° = 87 65°02,3' N., | 23°56,2) W., — 110 — _ = 92 64°44 N;, 32752’ W., — 976 — Tee — > OF Opal! N., 30°39! W., — 752 -- Aa = = 98 65°38 N,, 26°27" W., — 138 — 5,9° “Thor” 66°43’ N., 15°03’ W., —- 4 — Greenland: Davis Strait, depth 66 fathoms (without further details) Sukkertoppen, on Loltenia ( a) Godthaab, depth 50—60 fathoms Hunde-Kiland (without further details) Cape Tobin, depth 57 fathoms (East-Greenland Expedition) Jan Mayen: 70°32’ N., 8°z0' W., depth 470 fathoms Iceland: 4—5 miles E. of Bakkefjord, = — 5 miles E. of Seydisfjord, — 135 — 64°27’ N., 13°27’ W., — 150 metres The Faroe Islands: 61°40’ N., 7°40’ W., — 135 fathoms 6 miles N. by W. of Kalso, — 60 — Forma $revicyatha: The Faroe Islands: 7 miles N. by E. of Myggenees point, depth 57 fathoms 6 — N. by W. of Kalso — 60 — A rich and well-preserved material of Grammaria abietina from the Trondhjem Fjord afforded an opportunity for further study of the species. Its polyps have an oral part with mainly indifferent endoderm cells above the tentacle whorl; the true gastral endoderm exhibits an altogether uniform development. The base of the hydranth is fastened to the wall of the hydrotheca far in between the tubes of the rhizocaulome, by a wreath of small chitinous bodies; this is the only discernible limit between the hydrotheca and its mother stolon, which are otherwise practically of equal breadth. A study of the coppinia (Broch 1917) brought to light several peculiarities. In fertile colonies we find, 2* re] 20 HYDROIDA II in the defensive polyps and elsewhere, large, practically cylindrical nematocysts in addition to the small capsule form which is found in all thecaphores; the nematocysts are thus dimorphous. A remarkable feature about the coppinia is the position of the male gonothecz, which here appear as stalked, oval to spherical formations between the closely packed female gonothecee and the outer protective network of the tubes. Gvammaria abietina thus presents an intermediate stage between types with uniform, hermaphroditic coppinia, where the male gonothecee are wedged in among the female, and those where the male gonothece appear singly outside the coppinia or scapus, which has become an alto- gether female aggregate. The gonophores in Grammaria abietina exhibit distinct sexual dimorphism; the female gonophores are heteromedusoids, the male cryptomedusoids. The cryptomedusoid gono- phore is, however, here highly reduced, and distinctly presents a transition stage which would, on slight further reduction, become a styloid gonophore. From two places at the Faroe Islands we have in the material some very richly developed colonies which, owing to the somewhat divergent character of the hydrotheca, are here noted as representatives of a particular form, forma érevicyatha noy. In point of habitus, the mentioned colonies differ but little from forma /yfzca, they are of equally robust build, and with the same rich ramification; on closer examination, however, one cannot fail to observe the remarkable short hydrothece (fig. V). In forma /yAica, the hydrotheca protrudes its distal parts out in front of the stolons so far that the free portion of its upper (adcauline) wall reaches a length of 1,5 to 3 times the diameter of the aperture; in forma érevicyatha, on the other hand, the corresponding part is only one-half to one diameter in length. This might perhaps by some be regarded as a good specific character. We find however, here and there among the colonies, hydrothece presenting the same features as forma /yfzca, and, in slightly greater numbers, intermediate forms with lengths filling the interval between the dimensions named. On Fig. V. Grammaria abietina forma brevicyatha. ‘Terminal the other hand, these intermediate forms, and “/ypzca” hydrothecee occur part of of a branch. Colony from 7 miles N. by E. of Mygge- nes point, the Faroe Islands, ence upon the general character of the colony as a whole. How far we have 57 fathoms. (X 40.) only in so slight a percentage among the colonies that they exert no influ- here to deal with a local variant group, cannot be determined with certainty; that the form can hardly be very common in the northern seas is evident from its rare occurrence in the extensive material now being dealt with, even when this is supplemented by the large collect- ions from Trondhjem Fjord. Still, the form in question cannot be summarily disposed of by noting it under the head of casual single variants, since it occurs in a single colony from one place, but in four remarkably luxuriant ones from the other. Forma érevicyatha exhibits certain resemblances to Grammaria immersa Nutting; there are, however, so considerable differences observable that the two cannot be confused. The latter species is immediately recognisable from its finer structure, whereas Grammaria abietina is a species of very coarse build. The splitting of the tops of the branches (fig. V) in forma Jdrevicyatha also agrees with Grammaria abietina, as distinct from Grammaria immersa, A certain likeness to the latter species HYDROIDA II 21 again, we find in the shape of the hydrotheca; according to Kramp, (1911 p. 376) the margin of the hydrotheca in Grammaria abietina — in contrast to Grammaria tmmersa — always curves outwards slightly; in forma érevicyatha, on the other hand, this is only quite exceptionally the case, and by far the greater number of hydrothecee show no indication of outward curvature in the margin. Kramp has (1. c) pointed out another feature which is here of more importance. In forma drevzcyatha, the hydrotheca aperture is almost invariably turned somewhat obliquely upwards, not as in forma typica, where the plane of the aperture is parallel with the axis of the branch, or in Grammaria immersa, seessaeesensceceree 200 Mm. See SScS 000 MD: fone re nes OOO MM, Soo Seo eo OO Fig. VI. Localities of Grammaria abietina (forma brevicyatha +) in the Northern Atlantic. In the hatched region the literature notes a common, although scattered occurrence. where the opening is even turned slightly downwards. In forma drevicyatha, only the few large hydro- thecee have a plane of aperture parallel with the axis of the branch. Grammaria abietina is a typical arctic-boreal species, recorded also in a single instance (Bil- lard, 1904 p. 164) from the north of France. It may at times penetrate down to great depths, as for instance at the “Ingolf’ St. 92, where it reached 976 fathoms, the greatest depth hitherto recorded for this species. Otherwise itis chiefly found (see fig. VI) in the deeper parts of the littoral regions of the boreal and arctic area. Grammaria abietina is also apparently an Atlantic species; it is known from the east coast of North America, to Taimur, but has not hitherto been recorded from about Bering Strait or the Pacific. If, however, it should prove correct that Grammaria scandens Stechow is a synonym for Grammaria abietina, then it must be classed among the circumpolar species. 22 HYDROIDA II Grammaria immersa Nutting. Ig01 Grammaria immersa, Nutting, Papers from the Harriman Alaska Expedition, p. 178, pl. XXI, figs. 5, 6. The colonies form stiff, but finely built, irregularly ramified rhizocaulomes. The hydrothecze pass over into the stolon without marked constriction, their basal limit is formed by the series of small chitinous bodies to which the base of the hydranth is attached. Diaphragm lacking. The hydrothecze are tubular, highly curved in the distal part, and with no outward curvature of the opening margin. The aperture is normally turned somewhat obliquely down; more rarely, we may find the plane of the aperture parallel with the branch axis. The short freely projecting part has an upper (adcauline) wall in front of the stolons, its length being almost invariably less than half the diameter of the aperture, The gonothece are collected in close (hermaphroditic?) coppiniz, the tubes of which are highly curved, making a close network outside the gonothece. Material: Iceland: 8 miles E. of Seydisfjord, depth 60 fathoms (labelled Grammaria abietina). Grammaria immersa is an arctic character species; only quite exceptionally does it seem to penetrate into the boreal regions. It is circumpolar, and belongs to the littoral region. Gen. Lictorella (Allman). Upright colonies with sympodial growth. The hydrothecz deep bell-shaped to tubular, often exhibiting a slight asymmetrical development; they have a low yet strong diaphragm, but lack opercular apparatus. Nematothecee and nematophores lacking. Gastral endoderm of the polyps uniformly developed. Lictorella pinnata (G. O. Sars) Allman. 1874 Lafota pinnata, G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 94, tab. 4, figs. 25—28. 1874 — halectoides, Allman, Report on the Hydroida .... Porcupine, p. 471, pl. 66, figs. 1, 1a. 1888 Lictorella halectoides pars, Allman, Challenger Report vol. XIII, p. 35. nec 1907 Lafoéa pinnata, Browne, Hydroids collected by the “Huxley”, p. 25. Upright, single or double pinnate colonies, generally in one main plane, with polysiphonic main stem. The hydrothecz alternating in two rows along the branches, with a tendency to unilateral arrangement; the hydrothece all turned obliquely forward towards the one side (front) of the colony. The hydrothecee are narrowly bell-shaped, with slightly everted opening margin; transition to stalk gradual. The hydrotheca has a low but strongly developed diaphragm. Stalk generally short, with an oblique furrow on the upper side, at times also a furrow running right round the stalk lower down. The latter furrow runs transversely to the stalk. Polyps with uniform gastral endoderm. The gonothece are collected in an openly constructed scapus on the stem or main branches. HYDROIDA II 23 The single gonothece are reversed, narrowly conical to almost cylindrical, fastened to the hydrocaulus by a rudimentary stalk at the narrow end; distally, they are furnished with three, more rarely with four or two, round lateral openings, each with a short neck. Material: “Ingolf St. 7 63°13’ N, 15°41’ W., depth 600 fathoms 4,5° _ = 25 (ogy ING, GAPS Aig — 582 — 3,3° — - 81 61°44’ N., 27°00’ W., — 485 — 6,1° “Thor” GretsaNe, 9°33 W., =O /2eIIGLECS Levinsen (1913 p. 287) believes to have found a blind sack in ZLictorella pinnata; this must doubtless be due to an accidental S-shaped curvature of the polyp, which would not, however, produce 200 ™. sos oees VOOta 1o000m, eee OG TE Fig. VII. Finds of Zictorella pinnata in the Northern Atlantic. a blind sack of any real anatomical importance. Microtome sections reveal an entirely uniform gastral endoderm, and I have not been able to find any portion of the endoderm histologically corresponding to the epithelium in the blind sack of Sevtulariide. The “blind sack” observed must thus be due to accident. Lictorella pinnata exhibits a highly remarkable distribution (fig. VII). It belongs to the upper part of the abyssal region, but penetrates as far down as 1300 metres; on the other hand, the species can at times occur right up in the littoral region, and has been met with in the Hardanger Fjord even up at a depth of only 90 metres. Horizontally, the species seems to be quite widely distri- buted, but the few records from southern seas are unreliable, as the species has here been confused with Lictorella antipathes (Lamarck). Pictet and Bedot (1900 p. 16) record it from the Bay of Gas- 24 HYDROIDA II cogne. Browne’s specimens from the Bay of Biscay (1907 p. 25) on the other hand, should not be included here; from the nematothece, they should be ascribed to Zygophylax, and are plainly identical with the following species. In the northern Atlantic regions, the species appears to follow the warmer water-masses in their progress through the boreal regions; it has exceptionally been found right up in the Barents Sea. Gen. Zygophylax Quelch. Upright colonies with sympodial growth. The hydrothece are narrowly bell-shaped to tubular, not infrequently somewhat asymmetrical in structure, with a low, but strongly developed radially symmetrical diaphragm. The colonies are furnished with small nematothecze. The polyps have a uni- formly developed gastral endoderm. Zygophylax biarmata Billard. 1906 Zygophylax biarmata, Billard, “Travailleur” et “Talisman”, p. 180. 1907 Lafota pinnata, Browne, Hydroids collected by the “Huxley”, p. 25. gtr Lictorella Levinsent, Semundsson, Bidrag til Kundskaben om de islandske Hydroider II, p. 86. nec 1913 Zygophylax biarmata, Stechow, Hydroidpolypen der Japanischen Ostkiiste, p. 114. Colonies upright, in a plane singly or doubly pinnately branched with polysiphonic main stem; the branches nearly regularly alternating. The hydrothece are alternately placed, turning obliquely forward towards the one side (front) of the colony; i. e. with a tendency to unilateral arrangement. The hydrothecee are mainly tubular, with slightly outward curving margin, narrowing evenly down- wards to a stalk of varying length, which has one or two more or less distinctly marked segmenta- tions. The hydrotheca has a well developed low diaphragm. At the base of the hydrotheca stalk, and occasionally elsewhere on the tubes, there are small, cylindrical nematothecze, attached to the tube or apophyse by a short and often indistinct stalk, generally in one piece. The apophyse has normally a couple of nematothece. The gonothece are collected in a primitive, open coppinia (hermaphroditic?) on the stem or main branches; the nematothecee are more richly developed in the gonotheca aggregate than elsewhere, and appear there in large numbers. The gonothece are flattened ovate, with an outward and down- ward curving neck distally on either side in the transversal plane. Material: Iceland, near Vestmanné, depth 510 metres. (Type specimen of Lictorella Levinsent). The first description of this remarkable species is that given by Billard (1906 p. 180) who had, however, only sterile colonies to go upon. It is undoubtedly the same species which Browne records (1907 p. 25) from the Bay of Biscay, though he ascribes it incorrectly to Lafoéa pinnata G. O. Sars; the nematothecee show that it must be a Zygophylax, and the exhaustive description very di- stinctly suggests Zygophylax biarmata. Se mundsson (1911 p. 86) describes the species anew under HYDROIDA II c the name of Lictorella Levinsent, and notes the nematothecze as among its characteristic features; his colonies, which I have had an opportunity of examining, are fertile, wherefore he was also able to describe the gonosome. This is of a highly peculiar character, and at once demonstrates the incorrect- ness of Stechow’s supposition (1912 p. 114) that the species should be identical with Zygophylax armata (Ritchie). Ritchie’s species (1907 p. 533) has a typical coppinia, the tubes of which are each furnished with several nematothece. The single gonothece in Zygophylax brarmata resemble not a little those of Lzctorella pinnata, the number of opening tubes, however, being apparently in Zygophylax biarmata constantly reduced to two, the tubes being at the same time somewhat longer. The single gonotheca stands out freely, but the gonothece are closely packed in clusters on the stem or main branches, and between them we find numerous long nematothecze, remarkably well developed, so that the whole aggregate must be regarded as a primitive coppinia, or rather as something between the open scapus and the coppinia. There are one or two points which seem to count against the identity of Zzctorella Levinsent and Zygophylax biarmata. Seemundsson’s description rather gives the impression that there are not, normally, a pair of nematothecze on the apophysis; on closer investigation, however, we are led to the conviction that there are, as a rule, a couple of holes in the periderm showing that nemato- thecee have been there, but have fallen off. The colony investigated is the same which Semunds- son shows in fig. 2a. — A further difference would seem to exist in the hydrotheca stalks, which in Semundsson’s specimens are somewhat longer in proportion than stated by Billard. The length of stalk, however, varies considerably in hydroid species, and cannot thus be used as a specific char- acter. And finally, the hydrotheczee in the colony here concerned exhibit a tendency to unilateral arrangement. Semundsson does not mention this feature, nor does Billard make any reference to the same in his exposition. It would nevertheless seem, from Billard’s figure (I. c. text fig. 8) that the hydrothecze point obliquely forward towards the one side, the hydrothecee shown being indic- ated in oblique projection, with the aperture directed slightly forward towards the observer. Here again then, there is nothing which can be taken as evidence of distinction in species. The find here recorded extends the known distribution of this deep-sea form considerably towards the north, the species having hitherto been known ouly from the Bay of Biscay and south of the same. It appears to belong to the abyssal region. Family Campanulinide. The hydrothecz are tubular to bell-shaped, sessile or stalked, of the radially-symmetrical type, more rarely with diaphragm. The hydrothece are furnished with highly organised closing apparatus, falling in the shape of a roof or a pyramid over the indrawn polyp. The colonies are stolonial or sympodial. The polyps have a conically pointed oral part, and gastral endoderm of uniform organisation. The generic division of this family has given rise to much dispute, and we even find, that certain writers, such as Schneider (1897) and Bonnevie (1899) regard it as a single genus. The The Ingolf-Expedition. V. 7. 4 26 HYDROIDA II best exposition of the family is that given by Kramp, who has in two works (1911 and 1913) given a close description, which as regards its main features, is adhered to in the present work. Kramp (1913 p. 14) inclines to the view that the family should be divided into two, a primitive family, Cus- pidellide, where the closing apparatus is formed by the upper part of the hydrotheca wall, and a more highly developed family, Campanulinide, where the closing apparatus consists of the original roof of the hydrotheca. Kramp’s point of view is doubtless highly correct, but as my material is not suited to serve as basis for more detailed exposition, I have merely noted the two mentioned groups as sub- families, otherwise following mainly the generic division established by Kramp (1911 p. 383). The gonothecee in several members of the family are of considerable interest, differing only in their greater dimensions from the hydrothecee — doubtless a primitive feature. This peculiarity is known among the genera of Stegopoma, Cuspidella, and Lafoéina. Unfortunately, very little is known as to the gonophores, but we know that the family comprises the polyp-generation of a number of highly heterogeneous Leptomeduse, which are distributed by systematists throughout a whole series of families. As, however, the polyps, save for the mentioned characters in the sub-families, exhibit very considerable uniformity, we can hardly, from what we know at present, consent to a further sub- division of the family. We have evidently here to deal with a series of biological divergencies in the medusa generation, particularly calculated to demonstrate the impossibility of establishing, in the pre- sent state of our knowledge, any common system for the two generations. The hydroid system cannot here be adapted to the medusa system, which evidently demands thorough investigation of the biolog- ical adaptation phenomena in order to give a system which can claim to be considered as fairly satisfactory from a phylogenetic point of view. Sub-family Cuspidelline. Campanulinide with closing apparatus formed by the integrating distal part of the hydro- theca wall. Gen. Stegopoma Levinsen. Colony creeping or developed to an upright rhizocaulome. The hydrothece tubular to narrow bell-shaped, without diaphragm; the closing apparatus consists of two folding membranous parts of the distal hydrotheca wall, which shuts down in a roof-shaped lid over the aperture, between two diame- trally opposite teeth. The polyps have uniform gastral endoderm. Stegopoma plicatile (M. Sars) Levinsen. 1863 Lafoéa plicatilis, M. Sars, Bemeerkninger over fire norske Hydroider, p. Bite 1874 Calycella plicatilis, G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 95. 1893 Stegopoma plicatile, Levinsen, Meduser, Ctenophorer og Hydroider, p. 37. 1893 — caricum, Levinsen, — a - — p37: HYDROIDA II 27 Colonies form upright, irregularly pinnate, polysiphonic rhizocaulomes, sometimes with creeping parts. Hydrothece long, tubular, some quite free and short-stalked, others with the one side for part of its extent fused with the stolons; more or less curved, exceptionally with the distal part almost perpendicular to the proximal. Diaphragm lacking. Closing apparatus formed by two folding thin distal portions of the hydrotheca, shutting in a roof over the indrawn polyp between two strong, tooth- like, diametrically opposite parts of the distal portion of the hydrotheca. The gonothece are situated on the branches or on the stalk. They present the appearance of gigantic hydrothece, with the same structure of the closing apparatus. The gonothecz are entirely free, short-stalked, or to a greater or lesser extent attached to the tubes. Material: “Ingolf St. 28, 65°14’ N., 55°42’ W.; depth 420 fathoms, 3,5° — = 2, Oey ING, —syiPaad NWS — 68 —_ 0,2° = OA INI a aey \NGE — 318 =— 3,9° Snes en O5re7. NSA Zac; =, §5¢ = — = Bi (sada) IN) Stays? \WIG — 362 -- 3,6° — = 20,0 O72 TOWeNE 5520 \WVes — 203 — —0,5° Greenland: Davis Strait (without further details) depth 80 fathoms Umanak ( — — — ) Ritenbenk ( — — — ) on ga crenulata Godhavn ( — — — ) Kara Sea, “Dijmphna” (Type specimen of Stegopoma caricum.) This remarkable species shows an astonishing power of altering its appearance. One variant is described by Levinsen (1893 p. 37) as a distinct species, Stegopoma caricum, from the fact that it has, at the points of the branches, only three hydrotheca-bearing stolons. This feature, however, as I have previously pointed out (1912 p. 11), cannot be maintained as a specific character, since it may occur in certain branches, while others of the same colony have four or five such tubes near the point; very rarely, again, we may find the number of hydrotheca-bearing tubes reduced to two. It was also pointed out, on the same occasion, that the hydrothecze can vary, being at times entirely free, at others fused with the tubes. Free hydrothecze on creeping stolons assume entirely the same appear- ance as in Stegopoma fastigiatum (Alder). The gonothecze are mentioned several times in the literature, and have been described by Bonnevie (1899 p. 73) as follows: “Gonangia large, cylindrical with circular opening at the distal end”. Kramp, (1913 p. 16) on the other hand, describes them in the same manner as noted in the diagnosis, and gives excellent drawings. In the very extensive material at my disposal from Trond- hjem Fjord, where the species is extremely frequent, I have often had occasion to observe the gono- thecze, which in all cases agreed with Kramp’s description. It might be imagined that the gono- thecze would exhibit sexual dimorphism; up to the present, however, I have not been able to find anything in support of this idea, and it must thus be presumed that the earlier descriptions were based upon inadequate observation of the gonothece. 4* 28 HYDROIDA II Stegopoma plicatile is an arctic species, which can nevertheless penetrate into the boreal region (fig. VIII); its occurrence is, however, somewhat of a mystery. The species must be described as circumpolar, having been recorded from Davis Strait through the Norwegian Sea, the Barents Sea, the Kara Sea, and the Siberian Frozen Sea to the Bering Sea and the Sea of Okhotsk. Bathymetri- cally it is mostly found in the lower part of the littoral region. From this, then, the species should be noted as arctic; as a matter of fact, however, this would not agree with the data from the northern Atlantic regions. There are a couple of isolated finds from the cold area, but the species has not yet been noted either from the east coast of Greenland or from the eastern side of Davis Strait, and 200 m. SS Oise ee -- 1000m. Spt Ss OOO Fig. VIII. The occurrence of Stegopoma plicatile in the Northern Atlantic. In the hatched parts the literature notes a scattered, although common occurrence. also appears to be entirely lacking in Iceland waters. On the other hand, we find that it is very common along the eastern side of Davis Strait, and — according to the records — along the west coast of Norway; i. e. just in those places where the warmer water layers predominate in the bathy- metrical area of its distribution. It may also be noted, in this connection, that the species occurs on the Lophohelia reefs in the Trondhjem Fjord, in quantities unknown elsewhere. This occurrence is altogether mysterious in the case of a species otherwise only met with in high arctic waters; one would naturally expect that any extension of its distribution would follow the colder eastern shores, not the boreal western coasts of the continents. It is difficult at present to give any satisfactory explanation of this peculiarity. HYDROIDA II 29 Gen. Cuspidella Hincks. Stolonial colonies, with stalkless, sessile tubular hydrothecee. The closing apparatus is formed by an integrating distal portion of the hydrothecze, which folds conically over the indrawn polyp; there is no distinct limitation between the closing apparatus and the remainder of the hydrotheca. Nematothece lacking. Cuspidella humilis Hincks. 1863 Campanularia humilis, Hincks, M. S., Alder, Supplement to a Catalogue of the Zoophytes, p. 239. 1866 Cuspidella humilis, Hincks, On new British Hydroida, p. 298. Creeping colonies with cylindrical or slightly downward tapering hydrothece, passing over without stalk into the stolons. The hydrothece are set perpendicularly on the stolons, and are short, with a closing apparatus in which 10—12 segments can be distinguished. The gonothecz are set on the stolons, and are of the same shape and appearance as the hydro- thecee, but much larger. The gonophores develope into free medusz. Material: “Thor” 64°16’ N., 22°r7’ W., depth 50 metres Reykjavik, from the bottom of a well-boat. This unpretending little species seems to have a fairly wide distribution, and has been met with from the Siberian Frozen Sea down to the Cape Verde Islands. Nevertheless, the few finds le very wide apart, probably owing to the fact that the species, from its insignificant size, easily escapes observation. Its principal bathymetrical occurrence lies in the middle portion of the littoral region. Gen. Lafoéina M. Sars. Stolonial colonies with stalkless, sessile hydrothecze and nematothece. The closing apparatus of the hydrotheca is formed by the integrating folding part of the hydrotheca, and passes over without distinct limitation into the same; it closes conically over the indrawn polyp. The nematotheca has a distal laterally situated aperture. Hadii points out in a letter that there are possibly two genera concealed under this definition. According to the drawing given by G. O. Sars, of La/oéima tenuts (1874, tab. V, fig. 3), there seems to be a diaphragm occurring in this species at the junction of the hydrotheca and stolon. Levinsen (1893 p. 40) was not able to find any diaphragm in Za/oéina maxima, and I have likewise been unable to find any such here; my material, however, is of such a nature that a negative result cannot be considered as of decisive importance. Should it be found that certain species have a diaphragm, while others lack the same, it will then doubtless be most correct to divide the genus, and a further investig- ation of Lafoéina tenuis must then decide which of the two groups is to retain the name La/oéina. 30 HYDROIDA II Lafoéina maxima Levinsen. 1893 La/oéina maxima, Levinsen, Meduser, Ctenophorer og Hydroider, p. 182, tab. IV, figs. g—12. The colonies form upright, robust rhizocaulomes, often combined with creeping parts, which spread out in plates over the underlayer. The closely set hydrothece are cylindrical, somewhat irregul- arly bent, with their outer portion nearly perpendicular to the branch axis. The hydrotheca has a conically closing distal portion, exhibiting no distinct limitation from the remaining part of the same. Between the hydrothecee are the nematothecz, which are very numerous, and closely packed; they are slender, cylindrical, somewhat irregularly curved, with a distal, laterally situated oval aperture, in which are some few large nematocysts. The gonothece are wedged in between the nematothecee and the hydrothecz; they differ neither in form nor in size from the hydrothece, and their nature can thus asa rule only be determined from section preparations. Material: “Ingolf’? St. 29 65°34’ N., 54°31’ W.; depth 68 fathoms 0,2° = ea gd 8057 NG gta We nS ee — Holstensborg Harbour — 30 -- Greenland: Egedesminde (without further details) Store Hellefiskebanke, depth 24 fathoms j : ) — — north of Holstensborg ( — — — ) tev insen ) type- specimens Holstensborg ( Godthaab, depth 60—70 fathoms Davis Strait — 100 a Iceland: Hrutafjord, depth 45 metres. Lafoéina maxima is a typical arctic species, belonging to the upper half of the littoral region (fig. IX). The most southerly records of its occurrence are from Godthaab in Greenland, and Hritta- fjord in Iceland; in the Norwegian waters it has hitherto only been met with in Ramfjorden, near Troms6 (about 69°30’ N.) Gen. Campanulina van Beneden. Colonies with sympodial growth and stalked, radially symmetrical hydrothece. The closing apparatus of the hydrotheca is formed by the distal folding portion of the hydrotheca wall, and goes over into the same without sharp limitation. When folded down, the closing apparatus covers the hydrotheca with a conical lid. The gonothece differ in appearance from the hydrothecz. Kramp, in his exposition (1911 p. 383) merely draws attention to the stalked hydrothece of the genus as opposed to the sessile in Cuspidella and Lafoéina. Further, secondary characters are, it would seem, here also to be found in the growth types of the colony, whether stolonial or sympodial. HYDROIDA II 31 Thus the two last-named genera have, as far as we know, always stolonial colonies, whereas in Campanulina they are invariably sympodial. Campanulina turrita Hincks. 1868 Campanulina turrita, Hincks, A History of the British Hydroid Zoophytes, p. 190, pl. 36, fig. 2. Upright sympodial colonies with monosiphonic hydrocaulus, ringed throughout. The stem slightly zigzag. Stemi and branches are divided into slightly pronounced internodia, bearing distally Scarcueatomncn 200 m. Senco cas YOO: tence ee. 1000 M. Ree orn BOO b Fig. IX. Finds of Lafoézna maxima in the Northern Atlantic. an apophysis and one or two short-stalked hydrothece; from the apophysis the next internodium projects. At irregular intervals, one of the hydrothecee is replaced by a branch, so that the colonies assume an irregularly bushy appearance. The hydrothecze are fairly large, and when closed, about twice as long as broad; they are practically cylindrical, with evenly curved proximal part. Diaphragm lacking. Closing apparatus passes over without distinct limitation into the lower portion of the hydro- theca wall; it closes conically over the indrawn polyp. The gonothece are set upon short, ringed stalks, projecting from the stem or branches beside the hydrotheca stalks. The gonothece are small, slender, reversed conical or cylindrical with gradu- ally tapering basal part; they are cut off transversely at the distal end. The gonophores develope (according to Hincks) into free meduse. 32 HYDROIDA II Material : “Ingolf’, Holstensborg Harbour, on alge. Greenland: Smallesund near Egedesminde, on alge. In one of the colonies from Smallesund, a distinct renovation is discernible; unfortunately, it cannot be determined with certainty whether the primary individual has been a hydrotheca or a gono- theca, but the size would seem to suggest a primary hydrotheca. We have in this case not a hetero- morphotic renovate, as the renovate is a fully developed, stalked hydranth. The instance in question calls to mind Levinsen’s description (1892) of renewal of individuals in certain Campanulariide. The new find of Campanulina turrita from Greenland is highly interesting. Since Hincks found the species in Ireland it has only been recorded by Levinsen (1893 p. 181) at Egedesminde; from Holstensborg Harbour, the “Ingolf’ brought home a whole series of finely developed colonies. Sub-family Calycellinee.' Campanulinde with closing apparatus formed by the original roof of the hydrotheca. Gen. Calycella (Hincks). Creeping colonies with tubular hydrothecze, the closing apparatus sharply marked off from the hydrotheca itself, and easily falling off. The closing apparatus is formed by the peripheral parts of the original hydrotheca roof, the central portion of which is discarded; the closing apparatus is a folding membrane folding conically over the indrawn polyp. The hydrotheca lacks diaphragm. Calycella syringa (Linné) Alder. 1767 Sertularia syringa, Linné, Systema Naturee, ed. 12, vol. 1, p. 1311. 1860 Calicella syringa, Alder, Descriptions of a Zoophyte..., p. 73. 1868 Lafota pygmea, Alder, pars, Hincks, A History of the British Hydroid Zoophytes, p. 205. Colonies creeping. Hydrothecee tubular, often somewhat bent, with slightly outward curving opening margin; they are borne upon stalks, short or long, furnished with a varying number of rings. The closing apparatus is sharply marked off from the thicker wall of the hydrotheca, and easily falls off; it consists of an entire membrane, which folds down on definite lines, forming a conical roof over the indrawn polyp. The gonothecee are attached by short, ringed stalks to the stolons. They are oval, smooth. Gonophores heteromedusoid. Material: “Ingolf St. 95 65°14’ N., 30°39’ W.; depth 752 fathoms, 2,1° iho 64°16’ N., 22°17’ W.; — 50 metres - 64°02’ N., 22°33°7 W.; — 34 — 1 As the genus Campanulina belongs to the preceding subfamily, the present subfamily should not be called Campa- nulininé but better Calycelline. Greenland: Godhayn Egedesminde ( Store Hellefiskebanke off Holstensborg, depth 18—20 fathoms Sukkertoppen, on o/tenia and on alg (without further details) Davis Strait, Iceland: Seydisfjord Vadlavik Rodefjord Djupivogur Vestman6 Skagi Hvaltjord Stykkisholm Onundarfjord Skjalfandibugt Bredebugt 65°17,5’ N., HYDROIDA II (without further details) ) depth 80—100 fathoms — pee GENt a= 80 — 95 metres 8 fathoms IO—I5 — 40 metres 1 Oe 30 fathoms Io — 28 — 23°32’ W., depth 7—12 fathoms 6 miles W. of Iceland (without further details) The Faroe Islands: 6 miles N. by W. of Kalsé, depth 60 fathoms Deep hole at north point of Nols6, depth roo fathoms. Fig. X. The distribution of Calycella syringa in the northern Atlantic. In the hatched regions the literature denotes a common occurrence. The Ingolf-Expedition. V. 7 7. Sos ees s UO twee eee 000M, era rb n 34 HYDROIDA II It is evidently this species which is partly mentioned under the term La/foéa pygmea; according to Hincks (1868 p. 205) some of Alder’s original drawings show a conical lid in this species, which at once shows that Alder’s specimens, or at any rate some of them, must have been Calycella syringa. That Lafoéa pygmea is here only partly noted as synonymous with this species, is, as indicated under Lafoéa gracillima, owing to the fact that several writers at any rate have recorded creeping colonies of the latter species under the same name. Calycella syringa appears to be a wholly cosmopolitan species, which has been met with in all seas. Its bathymetrical area is very extensive, ranging from about 6 metres down to nearly 1500; it should nevertheless be observed that its occurrence in the abyssal region is exceptional, its chief area of distribution being restricted to the middle and upper parts of the littoral waters. Within the area investigated (fig. X) we find that it is apparently lacking along the greater part of the east coast of Greenland, where it is first met with far to the north, about 76° N. Its occurrence under high arctic conditions is altogether scattered, save where an intermixture of warmer water is discernible. Gen. Tetrapoma Levinsen. Stolonial colonies with tubular or narrowly bell-shaped hydrothecee without diaphragm. Closing apparatus formed by the original roof of the hydrotheca, and separated by a marked limitation from the thicker hydrotheca wall; it consists of (four) separate triangular plates, each attached in a sinus, between as many hydrotheca teeth. The polyps have a uniformly developed gastral endoderm, and lack outer ectoderm lamella. In a previous work (1909 p. 165) I united this genus with ZLovemella. Kramp (1911 p. 383) separates them again as two genera, chiefly, it would seem, on account of the number of plates in the lid. This feature can hardly be called important as a generic character; there is, however, another distinguishing feature of greater significance, which renders it necessary to separate the two genera. Hincks (1868 p. 178) especially mentions in Lovenella clausa (\Lovén) the presence of a diaphragm, a formation which does not appear to be found in Zetrapoma quadridentatum, and which warrants generic distinction. Secondarily, this separation is supported by the fact that Ze¢vapoma has stolonial colonies, while those of Lovenella are sympodial.' Levinsen (1913 p. 283) observes in a footnote, regarding Zetrapoma, “This genus must, no doubt, be united with Zhyroscyphus”. In this I am for several reasons unable to concur. In the first place, Zhyroscyphus has a distinct diaphragm, and hydrothecze of bilateral structure; in the second, the structure of the polyp also is entirely different. Zhyroscyphus, with its ectoderm lamelle and inci- pient blind sack formation, as also the differentiated gastral endoderm, exhibits closer relationship with Sertularnd@, and should probably far rather be considered as a primitive genus of this family. Tetrapoma quadridentatum (Hincks) Levinsen. 1874 Callycella quadridentata, Hincks, On deep-water Hydroida from Iceland, p. 149, pl. 8, figs. 17—20. 1893 Zetrapoma quadridentatum, Levinsen, Meduser, Ctenophorer og Hydroider, p. 180. ’ Comp. also Lovenella corrugata Thornely (Broch 1914 p. 32). ios) On HYDROIDA II Creeping colonies with tubular hydrothece. The hydrotheca stalk is irregularly, but distinctly ringed or spirally coiled. The hydrothecee pass over evenly into the stalk, they are somewhat expanded at the base, then tapering slightly upwards, to expand again a little towards the open- ing margin, which curves somewhat outwards. The opening margin itself has four low, but distinctly discernible teeth, and has four triangular opercular plates fastened between them. The gonothecze are unknown. Material: Greenland: Egedesminde, depth 30—s5o0 fathoms. Scattered specimens of this high-arctic species have been found at West Greenland, Spitzbergen, in the Murman Sea, the Barents Sea, the White Sea, the Siberian frozen Sea and the Sea of Okhotsk, and must thus doubtless be referred to the circumpolar species. It belongs to the middle parts of the littoral region. Family series Haleciina nov. Family Haleciide. The hydrothecz are radially symmetrical and very small, at times practically altogether dis- appearing; they have as a rule a basal cavity, often marked off from the hydrotheca itself by a dia- phragm. The hydranths are large, and cannot be drawn quite into the hydrothece. They have a conical proboscis, and their gastral endoderm falls into two divisions, answering to the fore-stomach and stomach of the polyp, which as a rule are separated by a limit indicated by a more or less marked ring furrow round the body of the polyp. The basal part, the stomach, forms the digestive portion. The polyps are radially symmetrical in structure. The colonies are stolonial or sympodial, with simple or derived growth of the tips. Gen. Halecium Oken. " Creeping stolonial, or upright sympodial colonies with small radially symmetrical hydrothecz with basal cavity. The diaphragm can be present or lacking. Nematothecee and nematophores lacking. The gonophores are developed in gonothece. The Haleciwm colony, in species with polysiphonic stem, often presents a peculiar appearance, differing greatly from that of other hydroid colonies, as the polysiphonic main stem, which is gener- ally very strongly developed, most frequently presents the same impression as an altogether irregularly branched rhizocaulome, while the outer parts of the branches almost always exhibit regular ramifica- tion. Halecitum minutum Broch especially, seems in some respects to take up a remarkable and exceptional position; according to Kramp’s observations (1913 p. 5) it can at times exhibit large colon- ies of composite structure with rhizocaulome-like polysiphonic main stem and main branches, while _ otherwise, the species normally presents: small, monosiphonic colonies proceeding from a network of 5 36 HYDROIDA II creeping stolons. This thus confirms, as Kramp points out, the doubts which have been expressed by certain previous writers as to the fundamental importance of the structure of the colony for hydroid systematics, and partly effaces the limit between creeping species and species with upright, composite colonies. The genus Halecizm is characterised by the lively renovation of its hydranths. This should, it would seem, be explained as due partly to the lack of special defensive individuals, partly to the minimal size of the hydrothecz, and finally also to the large dimensions of the polyps, which probably render them particularly attractive to creatures preying upon hydroids generally. The marked reno- vation activity often leads to the formation of whole piles of hydrothecze, or apparently small branches, for which Schydlowski (1901) has introduced the term “pseudohydrocauli”. Not infrequently also, heteromorphotic renovates may be observed; I have previously (1909 p. 151) noticed that the formation of gonothecze as heterorenovates is characteristic of the male in Ha/e- ctum ornatum Nutting. Heteromorphotic renovates of a more accidental nature will be noted later on in several species; these are of great interest, since renovates of this kind have, according to Hadi (1915) only been met with in nature among Halectum and Synthectide. The question has, however, been too little studied as yet to permit of our drawing further conclusions from this, but the point should be kept in mind, until it has been fully cleared up. Halecium halecinum (Linné) Oken. 1758 Sertularia halecina, Lanné, Systema Naturae, Ed. 10, p. 809. 1815 Halectum halectnum, Oken, Lehrbuch der Naturgeschichte, vol. 1, p. oI. Stiffly built, as a rule doubly pinnate colonies with polysiphonic main stem. The branches are as a rule pinnately ramified in the same plane as the main stem, or the colonies may, more rarely, assume an irregular bushy shape. The minor branches are divided up into regular internodia, the length of which is about twice the distal breadth. The primary hydrothecz are low, often almost like a mere opening in the branch apophysis at the distal end of the internodium. ‘The secondary hydrothecee are small, with a large basal cavity, generally somewhat asymmetrically developed, and having the basal part of its adcauline wall highly concave. The hydrothecee are somewhat broader at the aperture than at the well-developed, fairly strong diaphragm; the opening margin is not curved outward. The gonothece are large, and proceed from the apophysis at the base of the primary hydro- thece. The males are narrowly cylindrical to elongated oval, tapering below, distally cut off trans- versely, or more often broadly rounded. The female gonothece have a distal laterally placed aperture with a pair of hydranths; the aperture is furnished with a short cylindrical neck, and situate normally at the distal end of the hydrothecze; more rarely, the distal part of the gonotheca may be domed somewhat forward, so that the opening is a little below the point. The gonotheca is slender, almost entirely straight or slightly convex on the side opposite the pair of hydranths, and tapering evenly downwards. HYDROIDA II ey/ Material: “Ingolf? St. 7, 63°13’ N., 15°41’ W., depth 600 fathoms, 4,5° — EEO OAT Sun Nin 2772 OO UNV. — 295 = 5,8° - - 54, 63°08 N., 15°40’ W., — 601 — 39° AME” 63°30’ N., 20°14’ W., — 80 metres — [labelled Halecitum halecinum, H. Beanu and H. labrosum). Greenland: Cape Tobin, depth 57 fathoms (East Greenland Expedition). Iceland: Vadlavik (depth not stated) Vestman6, depth 30—40 fathoms [labelled Halectum halecinum and H. Beanit| 10 miles W. of Akranes (depth not stated) [labelled Halectum Beanz). Between Iceland and The Faroe Islands, depth 192 fathoms (without further details) The Faroe Islands: 6 miles N. by W. of Kals6, depth 60 fathoms Stokken 2 miles in $.22E, — 55 — Deep hole at north point of Nols6, depth roo fathoms. Glyversnes near Thorshayn, on red alge. Borénees 13 miles in N.75W., depth 30 fathoms. Halecium halecinum is generally of somewhat coarser build than Halectum Beanit, but a good deal finer than Haleciwm scutum; it is often extremely difficult to distinguish these species one from another, especially when the colonies assume an altogether irregular form, which the males in particular are inclined to do. The female gonothecee in Haleciwm halecinum will, in their normal shape, with the quite terminal lateral opening, hardly be confused with normal individuals of the other species, but when, as not infrequently occurs, the distal portion of the gonotheca is domed forward, so that the aperture is found somewhat below the point on one side of the gonotheca, the identity is by no means easy to determine. True, Halectum scutum is in most instances of far coarser build than the two others, but the variation in dim- ensions is within each of the three too great to permit the fixing of proper size Fig. XI. Halectum hale- limits; they would be found to overlap considerably. A useful general character ¢j2. Internode with hydrothece. From the Faroe Islands at north the secondary hydrotheca (fig. XI); the basal part of the adcauline wall is more point of Nols6. (> 60). for Halecium halecinum is the asymmetrical development of the basal cavity in strongly developed, and highly curved, so that the hydrotheca axis thus diverges widely from the branch. On the other hand it must be remarked that the hydrotheca aperture is perpendicular to the longitudinal axis, a feature whereby the species is distinguished from //a/eciwm Beanit. Halecium halecinum has an extremely wide area of distribution, and is very common right up in the Mediterranean; it has also been recorded from waters south of the Equator. In the northern waters, the species appears as a boreal character form, with warmer tendency (fig. XII) and is mostly met with in the middle part of the littoral region; at times, however, it may penetrate right down into the abyssal, as at the “Ingolf” St. 54, where it was taken in a depth of over 1300 metres. In purely arctic waters, it is very rare, and records of its occurrence there must be treated as doubtful, as it 38 HYDROIDA II has evidently on several occasions been confused with Halectum scutum. ‘The same applies in part to certain of the records from southern waters, where the species has undoubtedly often been mixed up with Haleciwm Beanit. Halecium Beanii Johnston. 1847 Hfalecitwm Beanit, Johnston, A history of the British Zoophytes p. 59, pl. 9, figs. 1-2 Upright densely built colonies with polysiphonic, fairly robust main stem, and monosiphonic, > ¢ 7 / ’ nnnately ramified outer branches; the ramification of the colony presents as a rule a main plane. The 5 } I Heretereaceeste na OOM: Sseaisw a Ceom: Fig. XII. The distribution of Halecium halecinum in the northern Atlantic. In the hatched regions the literature denotes a common occurrence. minor branches are divided into slender regular internodia; the distally situate, hydrotheca-bearing apophyse is almost of the same breadth as the branch itself, and sharply defined; the length of the internodium is about 2—2.5 times the distal breadth (including apophyse). The hydrothece small, bounded on the lower side by a slight diaphragm. The primary hydrothece are hardly more than an aperture in the apophyse, and the hydranth is evidently very soon renewed; the basal chamber of the secondary hydrotheca is symmetrical, with a distinctly marked basal expansion; above this the hydrotheca stalk is narrowest, its breadth increasing slightly from there until it passes over into the somewhat obliquely set hydrotheca; the latter is a little broader at the aperture than at the diaphragm; opening margin not outward curved. Gonothecze of medium size, proceeding from the apophyse of the primary hydrothece. The HYDROIDA II 39 males are very elongated oval, the females elongated oval to sausage-shaped, highly curved, with a short cylindrical neck in the middle or on the basal half of the gonotheca, and on the concave side of the same. Opening margin level; in the opening itself a pair of hydranths. Material: “Thor” 63°30’ N., 20°14’ W., depth 80 metres. The Faroe Islands: Borénzes 13 miles in N-75W., depth 30 fathoms. On a previous “occassion (1913 p. 13) I stated that Malectwm Bean should be regarded as a variant of Halecium halecinum; further investigations have, however, shown that this is not correct, even though the two species, more particularly 3 in a sterile state, may often enough be difficult to distinguish. Fertile female colonies are not easily confused, the form of the gonothecze being typically different; in comparison with the follow- ing species it should be noted that the aperture in Halectwm Beaniw lies roughly in a line with the basal and distal end of the gonotheca, and that the neck axis closely approaches, 1f not entirely coinciding with, this. line. (Fig. XIII). The bran- ches are, in Hlaleciwm Beanii, often slenderer than in Halecium halecinum and Halecitum scutum, and the apophyse is somewhat more marked; in addit- 4 : ion, the basal chamber of the secondary hydro- Fig. XIII. Halecium Beanii. theca is symmetrically developed, and not asym- a. Internode with hydrothece. 4. Gonotheca 9. From the metrical as in Halecium halecinum; finally also, Ee asa seh ais) anes Wg Sag the oblique position of the hydrotheca aperture as towards the axis serves to distinguish H/aleciwm Beanuw from the two related species mentioned. The geographical data for Haleciwm Beani are extremely unreliable as regards the northern waters; the species is, as I have frequently been able to perceive, often confused with Halecium scutum in arctic, with Aalectum halecinum in boreal areas. In all probability, it is a heat-loving form, which exceptionally penetrates into the northern waters. Halecium scutum Clark. 1876 Halecium scutum, Clark, Report on the Hydroids..... Alaska and the Aleutian Islands, p. 210, pl. 10, figs. 13—14. Robust colonies with polysiphonic main stem. The outermost small branches exhibit an almost regular pinnate ramification in the same principal plane as that in which the branching of the colony falls; more rarely, the colonies may be quite irregularly bushy. The minor branches are divided up _into internodia, the length of which is about twice the distal breadth (apophyse included). The primary 40 HYDROIDA II hydrothecze are low, often hardly more than an opening in the apophyse, which is distally placed, and distinctly marked. The secondary hydrothecz are likewise small, with a fairly large basal chamber, which is almost always symmetrically developed. The hydrothecee have a thin, but well-developed diaphragm; they expand towards the aperture, but have no outward curving margin. The gonothecce are small, and attached to the apophyse at the base of the primary hydrothece The males are cylindrical to elongated oval, tapering downwards, broadly rounded distally, or cut off transversely. The female gonothece have a laterally placed opening with a pair of hydranths; the opening margin has on its inner (adthecal) side a short, broadly lingueform protuberance. The gono- theca openings are situated between the middle and the distal end of the gonotheca, rarely quite distally. The gonotheca is often somewhat irregularly bent. Material: “Ingolf”’ St. 31, 66°35’ N., 55°54’ W., depth 88 fathoms 1,6° = =1934, “65207 No 0 5427 Wal a=) 50) as Greenland: Sukkertoppen (without further details) Davis Strait, depth 100 fathoms (without further details) [labelled //alectwm Beanit| Iceland: Vadlavik, (depth not stated) [labelled Halecium Beanii| Between Iceland and The Faroe Islands: 63°15’ N., 9°35’ W., depth 270 fathoms [labelled Ha/e- cium Beanit| The Faroe Islands: Deep hole at north point of Nols6, depth 1oo fathoms 61°40’ N., 7°40’ W., depth 135 fathoms Kara Sea: “Dijmphna” [labelled /aleciwm Beant}. It is not without a certain doubt that we can admit Halectwm scutum as a distinct species and not as an arctic form of Halecium halecinum. From a geographical point of view, as also with regard to most of the variational features, it stands in almost exactly the same relation to the last- named species as the arctic forms of several other more or less cosmopolitan hydroids. And it is also Halectum scutum which has formerly (Broch 1909 p. 144) been noted as forma pzgantea of Halecium halecinum., A comparison of the two species reveals various points of resemblance. Bonnevie’s state- ment (1899 p. 57) “ramification in all planes” as a characteristic feature cannot be admitted; it applies as a matter of fact far more to the exceptions, the great majority of the colonies exhibiting a decided main plane in which the ramification takes place. On the other hand, the short and broad internodia (fig. XIV a) are typical, and differ not a little from Hadlectam Beanit, with which the species has espe- cially been confused. The secondary hydrothece differ normally from //alectum halecinum in having a symmetrical and proportionately lower basal cavity, and from Hfaleciwm Beant in having the plane of the aperture perpendicular to the longitudinal axis. — The frequent confusion of H/aleciwm scutum with Halecium Beantt is due to the great variability of the female gonothece (figs. XIV é—) which not infrequently (e—/) resemble strongly those of the latter species. We should, however, note that in Halectum scutum the aperture and its short neck are as a rule obliquely placed, diverging widely from the line between the stalk of the gonotheca and its top; in addition, the gonotheca has an HYDROIDA II 41 adthecal lingueform protuberance which is lacking in Halectwm Beani. The extreme variants in the other direction, (4 and c; 4) are markedly suggestive of broadly built gonothecee in Haleciwm haleci- num, so that fertile colonies likewise may here often be confused. The illustration c shows a gono- theca which has arisen as a heteromorphotic renovate. ‘a b c a € Fig. XIVa—h. Halecium scutum. a. Internodium and secondary hydrotheca, Davis Strait 100 fathoms ( 60). é—e. Gonothece from a colony (9) in Kara sea (> 30). f—h. Gonothecee from a colony (9) in Davis Strait depth 100 fathoms (> 30). Every gonotheca contains fully developed planula larvae. The material includes several specim- ens of Halectum scutum which had_previ- ously been determined as Halecium Beanit; this shows, that extreme caution should be observed in dealing with records in literature of the last-named species, the occurrence of which under arctic conditions is, as above if s ie mentioned, doubtful. Aaleciwm scutum, on the other hand, is an arctic character form, with circum- polar distribution. In the waters investigated (fig. XV) it is found in the lower part of the littoral region, but quite exceptionally, as at the Faroe Islands, does it penetrate to any considerable extent into the warmer boreal waters. Halecium curvicaule v. Lorenz. 1886 Halecium curvicaule, v. Lorenz, Polypomedusen von Jan Mayen, p. 25, pl. 2, figs. 1—2. Colonies creeping or upright, with irregular, more rarely almost dichotomic ramification, mono- siphonic hydrocaulus. Hydrothece terminal: the next hydrotheca stalk or branch internodium proceeds The Ingolf-Expedition. V. 7. 6 42 HYDROIDA II from an almost spherical apophyse situate close under the terminal hydrotheca. The hydrotheca itself is low, somewhat broader at the aperture than at the faint diaphragm, more rarely with margin slightly bent over. Secondary hydrothecze occur in smaller numbers. The hydrotheca stalks are as a rule fairly long, as a rule with a couple of rings below. The gonothece proceed from the hydrotheca stalks close under the polyp, and are attached by a short, often almost quite rudimentary stalk, or are exceptionally formed as heterorenovates in the hydrothece. “The males are elongated oval or narrowly egg-shaped, attached to the colony by their narrower end. The female gonothece are practically pear-shaped, laterally compressed, and with a pair of hydranths in the distal, asymmetrically placed opening; on the side opposite this aperture, the wonerecessseece see 200 M, SSeS Sere jane ane ae eo O00 M1. sass ee essanes a COON Fig. XV. Finds of Halecium scutum in the Northern Atlantic. © Localities of Halectum Beani after Kramp (1914), referring to Halecitum scutum, gonotheca has 2—g9 transverse furrows, more or less pronounced, at times almost imperceptible; they never reach right round the gonotheca. “Ingolf’ St. 29, 65°34’ N., 54°31’ W., depth 68 fathoms, 0,2° Greenland: Egedesminde (without further details) Iceland: Bakkefjord, depth 1o fathoms Hvalfjord, — 46 metres. A detailed description of Halecium curvicaule has been given by Dons (1912 p. 61) who shows, that Halecium mirabile Schydlowsky and Halecium repens Jaderholm are synonyms to this species. HYDROIDA II 43 Examination of a large amount of material leaves no doubt as to the correctness of this. The species is enormously multifarious in its power of variation, and has a remarkable capability of changing its appearance; an examination of the branches, however, will always reveal the characteristic, almost spherical apophyse typical of the species, and the distinguishing characters established are seen to be founded on growth stages. Dons does not appear to have noticed that his figure D.5 shows how the male gonotheca can be formed in hydrotheca as a heteromorphotic renovate. This is particularly interesting in the case of the present species, since other heteromorphotic renovates likewise appear in the same in nature, as tendril-like stolon formations in place of hydranths. Dons mentions such renovates, with illustra- seeee 200 M. —----—--- 60cm. 9 twee ee fo0om. saeecesareni=eeen COO OTs 8 Fig. XVI. Localities of Halecium curvicaule in the Northern Atlantic. tions, and points out that these very features have served as the basis on which the species Halecium mirabile was established. The species is thus characterised by a less lively hydranth renewal, but has on the other hand a more marked tendency to form heteromorphotic renovates than most other forms of Halecium. Halecium curvicaule is a markedly high-arctic species, belonging to the littoral region. Only quite exceptionally does it penetrate into boreal waters (fig. XVI) as for instance at Iceland. Off the coast of Norway it has not yet been met with south of Bjarkoy. Halecium muricatum (Ellis and Solander) Johnston. 1786 Sertularia muricata, Ellis aud Solander, The natural history of many curious an uncommon Zoo- phytes, p. 59, pl. 7, figs. 3—4. 1847 Halecium muricatum, Johnston, A history of the British Zoophytes, p. 60, pl. 9, figs. 3—4. 6* 44 HYDROIDA II Upright colonies with polysiphonic, irregularly ramified main stem, and regular singly or doubly pinnate branches; the outer, minor branchlets regularly alternating. The hydrothecz small, with expanded margin, especially on the adcauline side; the basal cavity is large, somewhat asymmetrically developed, with a markedly convex adcauline wall and a straight or slightly concave abcauline wall, inserted asymmetrically on a laterally placed apophyse at the distal end of the internodium. The branches are divided into internodia, which often exhibit one or two basal constrictions. The gonothecze proceed from the tubes of the stem. They are large, somewhat flattened, and furnished with spiny longitudinal ribs on the flat side. Material: ° “Ingolf’ St. 29 65°34’ N., 54°31’ W., depth 68 fathoms 0,2 ae pea gd O51 IN: 54 hye eS aeee = - 84 62°58’ N., 25°24’ W., — 633 — 4,8° SRhor! 65°52’ N., 23°58’ W., — 62 metres -- 64°16’ N., 22°17’ W., —- 5 — = 64°16’ N., 11°15’ W., 37, = Greenland: Egedesminde (without further details) Store Hellefiskebanke ( — _ — ) Store Hellefiskebanke depth 24 fathoms Davis Strait ( ) 100 ~— Ingmikertok, Angmagsalikfjord (East Greenland Expedition) Iceland: Mouth of Hornafjord (depth not stated) Rodefjord, depth 80 fathoms Djupivogr — 8 — Vestman6 — 10-15 — 10 miles W. of Akranes (depth not stated) Stykkisholm, depth 30 fathoms Bredebugt 65°17’ N., 23°32’ W., depth 7—12 fathoms Adelvik (depth not stated), The Faroe Islands: 7 miles N. by E. of Myggenzs point, depth, 57 fathoms 6 miles N. by W. of Store Kalsé, — 60 — Deep hole at north point of Nolsé — 100 — 5 miles SSE. of Bispen — 5s — Forma a@ébyssalis: “Ingolf? St. 125, 68°08' N., 16°02’ W.; depth 729 fathoms, —o0,8° Flalecium muricatum, with its asymmetrically developed hydrotheca stalks or basal cavities and its slenderer form, stands out distinctly from the remainder of the northern Aaleczwm species, and is not easily confused. It is as a rule finely built, but may occur in large colonies with highly rami- fied polysiphonic main stem; the ramification then mostly proceeds in a main plane, but can also be altogether irregular, so that the colonies assume a quite bushy appearance. The margin of the hydro- HYDROIDA II 45 theca can vary with regard to curvature, and may in extreme cases somewhat resemble Halecoum labrosum; in Halecium muricatum however, we always find that the adcauline margin of the hydro- theca is more markedly curved, the abcauline less so. Normally, the length of the internodium is about three times its distal breadth (including the apophyse); we have, however, from the “Ingolf” St. 125, a colony which, from its extremely long inter- nodia, must be regarded as a deep-sea variant (fig. XVII 4), forma aéyssalis noy. It is not unusual among hydroids to find that the colonies from greater depths exhibit an extension of the single branch parts; in this case, however, the tendency is pushed to an extreme, and at a first glance, the colony presents an altogether alien appearance. It is probably due to the fact that the species here occurs in the cold area, at the considerable depth of 729 fathoms. The colonies are very slender, about 10 cm high, with polysiphonic stems. The internodia of the minor branches are 3—4 mm long, about five times the distal breadth incl. apophyse. The apophyse itself is very distinctly mar- ked and bears a slender hydrotheca. The hydrotheca has close under the diaphragm the typical adcauline thick- ening of the wall, the “pseudodia- phragm” which as a rule is also found 2 in the typical form. The hydrothecze Hie, Seat ee exhibit the form typical for the spe- Halecium muricatum. : _ Int i , cies; the secondary hydrothece are “ SUSEROGRIGE Ging) SE SOUn Scr i from a typical colony from Store comparatively short-stalked, butother- pyenefiskebanke, depth 32 fath. wise of the same shape as the pri- 4. Internodium with hydrothece mary. The colonies are sterile. From 0f forma a@éyssals from “Ingolf” St. 125. (X 40). b the features mentioned it follows that the colonies cannot be taken as representatives of a distinct species; they should, however, be distin- guished as the type of a particular forma aéyssalis of the original species. Halecitum muricatum is a circumpolar arctic species, able to penetrate into the boreal region and out to the limits between this and warmer layers (fig. XVIII). Its principal occurrence is restricted to the upper part of the littoral region, but it may, as seen from the foregoing, penetrate far down into the abyssal. It was met with already by the Norwegian North-Atlantic Expedition at a depth of 1350 metres. Halecium labrosum Alder. 1859 Halecium labrosum, Alder, Descriptions of three new species of Sertularian Zoophytes, p. 351, pl. 13. Robust, upright, and irregularly branched colonies with polysiphonic main stem. The hydrothecze are short, symmetrical, with markedly recurvate aperture margin. The basal cavity is very large, and bounded above by the base of the’ hydranth; the diaphragm rudimentary or entirely lacking. The 46 HYDROIDA II branches are divided into fairly short internodia, having a hydrotheca on the distal apophyse; the’ latter is often, though not always, separated from the basal cavity of the hydrotheca by a joint. The gonothece are very large, and proceed from the tubes of the stem and branches, or from the apophyse. They are irregularly oval, flattened, without spines or ribs, the females are much larger than the males, often more flattened in proportion, but otherwise of the same shape. Material: “Ingolf’? St. 33. 67°57’ N., 55°30’ W., depth 35 fathoms 0,8° Greenland: Egedesminde (without further details) Store Hellefiskebanke ( — a= oe) Davis Strait, depth 100 fathoms ( —- = —, )) = — 67°34’ N., 55°20’ W., (depth not stated) Iceland: Vadlavig, depth 46 fathoms Vestmano, — 28 — Halecium labrosuwm is an arctic species capable of penetrating into the boreal areas (fig. XIX). In strictly arctic waters it is of very robust build, perhaps the coarsest of all arctic Halecium species, and can hardly be confused with others. In warmer parts, it assumes a somewhat finer structure, but should even here be reckoned among the robust forms. Bathymetrically, the species belongs to the upper part of the littoral region, and has very rarely been observed below this. The few records of its occurrence in the Mediterranean and Atlantic south of the boreal region demand renewed investi- gation, as much would seem to suggest that confusion has taken place. Halecium tenellum Hincks. 1861 Hlaleciwm tenellum, Hincks, A catalogue of the Zoophytes of South Devon, p. 252, pl. 6, figs. r—4. ?ig11 Halectum textum, Kramp, Report on the Hydroids....... the Danmark Expedition, p. 368, pl. XXI, figs. 5—6. Colonies upright, with monosiphonic hydrocaulus, and typical, somewhat irregularly sympodial growth. The branches — the new hydrotheca stalks — proceed from close beneath the basis of the terminal primary hydrotheca, not infrequently in pairs, so that dichotomic ramification takes place; more rarely several branches from the same point. Pseudohydrocauli are of minor importance in the colonies, the renewal of hydrothecz is not particularly active. The hydrothecz are of medium size, broadening upward from the slight diaphragm and terminating in an often recurvate opening margin. The stalk of the secondary hydrothece is ringed, the branches are often ringed throughout their entire length, and exhibit at any rate distinct rings above their origin. The gonothecze proceed from the base of the primary hydrothece, or more rarely, they may be formed as heteromorphotic renovates in the hydrothece themselves. The gonotheca is somewhat flattened; viewed from the broad side they are elongated oval, with the distal part cut off transversely or broadly rounded; seen laterally, they are more egg-shaped, with a pointed distal part. They lack hydranth pairs. Material: “Ingolf St. 87 65°02,3’ N., 23°56,2’ W., depth 110 fathoms HYDROIDA II 47 sa 200M. Soo SS oq UCOGE Sp JOE a BOO Fig. XVIII. The distribution of Halecium muricatum (forma abyssalis +-) in the Northern Atlantic. In the hatched regions the literature notes a common, although scattered occurrence. Gussssieasseisanscsme COMI» Soe 605 UOT ao se (000M, Sater eo, a OOO Fig. XIX. The occurrence of Halecium labrosum in the Northern Atlantic. In the hatched parts the occurrence according to literature is scattered, no accurate details as to localities are given. 48 HYDROIDA II Greenland: Sukkertoppen, on Aoltenza (without further details). Iceland: Brunnes, depth 4 fathoms Seydisfjord — 6 — Hvalfjord — 46 metres Stykkisholm — 30 fathoms. The Faroe Islands: 6 miles N. by W. of Store Kals6, depth 60 fathoms Deep hole at north point of Nols6 — 100 — Glyversnees near Thorshavn, on red alge. There may be some possibility that the colony here shown (fig. XX) from the “Ingolf” St. 87 does not altogether agree with Haleciwm tenellum. On comparing with the des- criptions given by Hincks (1868 p. 226, pl. 45, fig. le), Rit- chie (1907 p. 525), and Jaderholm (1909 p. 14) the gono- thecee do not agree with those shown. Hincks describes them as follows: “the capsules vary in form, being broadly ovate, or slender and somewhat pointed above; they contain a single, large gonophore”. His figure shows us a slenderly oval or more pear-shaped gonotheca broadly rounded at the distal end. Ritchie’s description is as follows: “The gon- angia are ovate, broad in the proximal region, obtusely pointed in the distal. They are supported on short stalks, which arise from the sides of the hydrotheca, and always from the lowest segment in any hydrotheca tier’. Jaderholm writes: “Go- notheken eirund, unter den Hydrotheken ausgehend und (nach Fig. XX. Haleciwm tenellum. 9 from “Ingolf’ St. 87. By * a gonotheca formed as heterorenovate. thekenmtindung. Distale Zahne fehlen”. From the statements (X< 20). Thornely) auch von der Hydrorhiza und aus der Hydro- here quoted, it is not easy to gain a clear impression of the gonangia, and none of them will altogether cover the present fertile colonies, of which there are not a few in my material, and which agree with the specimen shown. The gonothecze are here set on short stalks, close under the primary hydrothece, or may exceptionally arise from the interior of the same; this agrees with the statements given above, as also with a later observation by Ritchie (1911 p. 30) where however, nothing new is stated as to their shape. The gonotheca contains, as Hincks points out, a single large gonophore, but the state of preservation of the material did not permit further investigation of this. On the other hand, the shape of the gonotheca agrees but ill with Hincks’s drawing, and forms rather a cross between the description given by Ritchie and that of Jaderholm, not improbably because the gonothecze are somewhat flattened. In lateral view, they are egg-shaped, with a broad basal part, and pointed distal end; viewed from the flat, on the other hand, they are more elongated oval, more or less trans- versely cut off at the distal end. On comparing this with the passage from Hincks’s description quoted above, we find that his expression “broadly ovate, or somewhat pointed above” agrees after HYDROIDA II 49 all, as long as we bear in mind that the two statements refer to the gonotheca as viewed in the one case from the flat, in the other from the side. Consequently, all things considered, I regard the col- onies in question as representatives of Hlaleciwm tenellum. Jaderholm (1909 p. 55) notes Halectwm Schnetdert (Bonnevie) (1898 p. 10) as synonymous with Flalecium tenellum; this, however, requires further justification. The shape of the colony, and the lively formation of pseudohydrocauli in Halecium Schneideri, agree rather with Halecium minutum, but the identity of the species is altogether doubtful, from the data we possess. Should the female gonothecz prove to correspond with Schneider’s Halectum nanum (1898 p. 481) then we have here a species entirely distinct from /aleciwm tenellum and Halecium minutum. Similarly, it may be doubtful 200 m. Be a veya OOO cas eee MOO OLIRT Cae ee a2 OOO: Fig. XXI. Finds of Haleciwm tenellum in the Northern Atlantic. whether the species noted by me (1913 p. 17) as Halectwm tenellum, from the Adriatic, really belongs here; the method of growth of the colony, and its dimensions, differ to such a degree from what is found in northern specimens of Halectwm tenellum, that we must await demonstration of the gonothece in the Adriatic form before we can determine with certainty whether it belongs to this species. The colonies agree on the other hand very well with the Welectwm textum described by Kramp (1911 p. 368); the marked curvature of the hydrotheca margin in this species is not more pronounced than is frequently met with in Ha@leciwm tenellum; here, however, we must also await the finding of gonangia. It would also seem likely, as Kramp (1914 p. 1003) points out, that the Hale- ctum crimis described by Stechow (1913 p. 79) belongs under Aalecium tenellum; Stechow’s inter- pretation of the manner of ramification in the colony is based upon an entirely erroneous appreciation / The Ingolf-Expedition. V. 7. 50 HYDROIDA II of the actual conditions; a point which has likewise been demonstrated by Kramp. Stechow’s drawings in the mentioned work are sadly schematic, and thus afford but poor support. Halectum tenellum belongs to the littoral region, and appears to occur but rarely deeper down in northern waters. From records in the literature, the species is altogether cosmopolitan, penetrating far into the Arctic waters, albeit it must here evidently have been frequently confused with the related Flalectum minutum. Despite the fact that it is cosmopolitan, its occurrence in the boreal waters (fig. XXI) is remarkably scattered, and apparently irregular. It is probably considerably more common than appears from the chart, but occurs often in insignificant little colonies which may easily escape notice. Halecium minutum Broch. 1903 Halectum minutum, Broch, Die von ... “Michael Sars” ... gesammelten Hydroiden, p. 4, Taf. I, figs. I—4. Colonies upright, generally with small, monosiphonic hydrocaulus, with regular, zigzag shaped sympodial growth; these small colonies arise as a rule from creeping stolons, but at times the stolons may collect together into well developed, branched and polysiphonic rhizocaulome-like formations, from which small branches with sympodial ramification proceed. New branchlets arise from under the base of the primary hydrothecz, normally only one branch at the hydrotheca. The renewal of the hydrothecee is lively, and gives rise to pseudohydrocauli, which may more rarely serve as the base for secondary sympodial formations. The hydrothecz are fairly large, expanding considerably upwards from the slightly developed diaphragm, and have asa rule a highly curved margin; the stalks of the secondary hydrothecee are ringed; the branches have distinct rings under the uppermost hydrothece, rarely elsewhere. The gonothece arise from the creeping stolons or from the tubes of the polysiphonic parts of the colony. The females are very large, up to 3 mm. long, broad oval to round, and may not infre- quently even be broader than long; they are highly flattened, with spines along the edge, especially in the distal part. The male gonothecze are smaller, elliptical, and smooth; they may also proceed from beneath the base of the primary hydrothecee. Material: “Thor” 66°19’ N. 23°14’ W.; depth 115—120 metres Greenland: Egedesminde (without further details) Iceland: g miles N.74°E. of Hornet, depth 38 fathoms Vadlavik, — 80 — [labelled Halectum tenellum| Djupivogr — §& — [ — -- — | 64°17’ N., 14°44’ W. — 75 metres [| -— — — | Skagi — 40 — Hvaltjord — 46 — [ — — Schneider | Skjalfandi Bay — 28 fathoms. Kramp’s studies (1913 p. 5) of Halectum minutum are highly interesting. He has succeeded in finding fertile female colonies, the identity of which is thus placed beyond doubt, but where the HYDROIDA II 51 He) tah ee SS boom. Can tens aod essen BOOOMT. ape erase aes, OOO Fig. XXII. Finds of Haleciwm minutum in the Northern Atlantic. small sympodial parts, normal in appearance, arise from enormous rhizocaulome formations instead of from creeping stolons. This, as Kramp also points out, places the question of growth conditions as generic character in a remarkable light; and what is worse, it shows us that the shape of the colony can even in specific limitation only be applied with great discretion, a point which has also been noted here under the heading of Lafotide. Kramp thus supports my supposition (1909 p. 153) that the colonies which Jaderholm (1907) mentions from the Bering Sea under the name of Halecium telescopicum should more probably be ascribed to Haleciwm minutum. Halecitum minutum is an arctic species which has doubtless a considerable distribution in the Polar Sea, but which is often confused with others, and especially with //aleciwm tenellum, as is also clearly evident from the list of investigation material given above. Apart from the Bering Sea, the species has been recorded at Spitzbergen, the Murman coast, east and north coasts of Iceland, northern east coast of Greenland, and several places along the west coast; finally also Fraser (1913 p. 168) has met with it at Nova Scotia, on the Canso Bank. The species penetrates but very slightly into the boreal region, as far as can be seen from the finds made up to now. Family Plumulariide. The hydrothece are small, sessile, approximately radially symmetrical, one side partly or en- tirely fused with the branches (tubes); the diaphragm is somewhat asymmetrical. The large polyps can practically speaking never be drawn entirely into the hydrothece. The sarcothece are two-chambered, a* / 52 HYDROIDA II stalked and mobile, or small, rudimentary or entirely effaced, being represented merely by holes in the periderm, at times with slightly raised, asymmetrical edges. The margin of the hydrotheca is almost always without teeth. The colonies are monopodial with terminal growth point. The gastral endo- derm of the polyp is divided into a fore stomach and a digestive stomach part, the limit between them appearing as a constriction round the body of the polyp. As thus defined, the family covers the group Lleutheroplea auctt. but it also further includes such primitive forms as Avrchenpaueria, which lacks true sarcothecee. What have been taken for such are in reality merely low, as a rule somewhat asymmetrically developed margins round the aperture in the periderm through which the sarcostyle passes out. This formation cannot be altogether regarded as a parallel to the sarcotheca, which forms the fixed point of support for the sarcostyle, and is as a rule furnished with a diaphragm in Plumulariide. On the other hand, it must be admitted that there are certain transition forms which render the limit between Plwmulariide and Aglaophentide somewhat indistinct at times, as we find species with both stalked mobile, and immobile, sessile sarcothecze; these forms must be regarded as primitive Aglaophenude. Such transition forms are also met with as against /aleciide, though it has not in this case been found advisable to unite the two families. We find, as a matter of fact, in almost every hydroid family such intermediate forms, the position of which is more or less a matter of doubt. If entirely definite boundary lines had to be drawn, it would very possibly involve the reduction of the entire group of hydroids to one or two families. But the heterogeneity would then be too great. In the same way, the Plumulariide, as viewed by Nutting (1g00) and Stechow (1913) make a too heterogeneous group, which as both writers also admit, really comprises two very well defined main groups. As these two main groups differ in principle, as much as any two families in the other family series of thecaphore hydroids, and as, moreover, the intermediate forms here are neither more numerous nor more marked than elsewhere, it will be correct to keep the two groups apart as sepa- rate families. Gen. Kirchenpaueria (Jickeli). Upright pinnate colonies, the stem bearing on its apophyses only undivided branches (hydro- cladia) with several hydrothece, these being unilaterally arranged, and fused with the branch. Beside the nutritive polyps appear the sarcostyles, which proceed from holes in the periderm; these holes are often surrounded by a slightly raised, as a rule somewhat asymmetrically developed periderm collar. Paired sarcostyles lacking. Bedot (1916) reintroduces this genus, and defines it further in such a manner that the old Sertularia pinnata linné appears as its typical species. In the list published in 1915, “Nomina conservanda. Unter Mitwirkung zahlreicher Spezialisten herausgegeben von Prof. C. Apstein” (Sitzungsberichte der Gesellschaft naturforschender Freunde, Berlin, Mai 1915) we find under polyps (p. 126—127) as type for Piamularia the Plumularia pinnata L. This is well calculated to show that a list such as the one mentioned may easily manage to defeat its own ends. Within the very large number of species which are referred to the genus Plu- mularia, the Plumularia pinnata takes up a quite exceptional position, owing to its reduced sarcothecee, HYDROIDA II 53 which are partly or entirely lacking. If we were to follow the list, we should then be obliged, as Pro- fessor M. Bedot writes me in a letter on this matter, to alter the generic name for all the over 200 species which have hitherto been noted under genus Plumularia. There is, as Professor Bedot further writes, nothing to suggest that Lamarck, the founder of the genus, ever regarded Plumularia pin- nata as the type species in preference to any other then known species of the genus. There would seem much more reason to establish Plumularia setacea as type species. That a generic distinction should be made between Plumularia pinnata and the remaining species, where the sarcothecee are far more highly developed, and generally appear partly paired, is beyond all doubt; this Stechow (1913 p. 25) also points out, and suggests Avrchenpaueria as generic name for the group, but without going further into the matter. There are indeed several objections to be made to the mentioned list as regards the hydroids. That the authors note the genera Clytia, Gonothyraea, Pasythea, Podocoryne, and Schizotricha, may be taken for a party contribution to the dispute as to leading fundamental principles in systematics, which has no place in such a list, given without justification or explanation; the effect here is merely to create confusion, not to form a basis for firm and tenable conditions. Here again there is no question of names rendered so familiar through the medium of the handbooks as to have any claim to acknow- ledgement on that count. Furthermore, the revival of a name such as Monocaulus is more confusing than the retention of the later, generally employed appellation Branchiocerianthus. ‘The authors have here evidently failed to realise that the type species given, zmferator, does not as a matter of fact occur at all in Allman’s original Monocaulus genus, which was founded on northern Corymorpha species with sessile gonophores, while the mentioned species was not found until later, by the “Chal- lenger”, and incorrectly placed in the genus A/onocaulus, with the original diagnosis of which the spe- cies does not agree at all. We may further note the question as to whether Anfennularia or Nemer- testa should be retained. The latter name is generally adopted in later works by Stechow, Broch and Billard, and is likewise recognised in Bedot’s eminent historical nomenclature studies, and neither of the names can be said to be of over frequent occurrence in the handbooks; the retention of Antennularia is here less due to sound defensible reasons than it is a matter of taste. — But we can- not here go farther into details with regard to this list; the foregoing will be sufficient to show that in its present form it is far from attaining the end proposed by discussion as to the retention of names whose alteration would bring about confusion in zoological handbooks and teaching works. As regards the generic name Avrchenpaueria, there may be some little hesitation. The name in question first appears as a synonym in Kirchenpauer’s paper Neue Bryozoen, Catalog IV des Museum Godetiroy, Hamburg 1869, where we find Azrchenpaueria elegans Greeff in litt. = Reichornia Greeffer Kirchenpauer. In the Bryozoa literature it occurs again only in E. C. Jelly, Synonymic catalogue of the recent Bryozoa, London 1889, as Avrchenpaueria elegans Graeffe, Kirch. in litt. — Jickeli introduces the name in 1883 for a hydroid which, as Bedot points out (1916 p. 641) is identical with Plwmularia pinnata, Strictly speaking then, we should according to the precise rules of nomenclature perhaps rather have taken another name, but I regard it nevertheless as most correct for the present to follow Bedot, as there can hardly be any risk of confusion thereby. The generic name A7zrchenpaueria is therefore here maintained for the genus whose type is Sertuwlaria pinnata Linné. Kirchenpaueria pinnata (Linné) Bedot. 1758 Sertularta pinnata, Linné, Systema nature, ed. 10, p. 813. 1916 Kirchenpaueria pinnata, Bedot, Sur le genre Kirchenpaueria, p. 645. Upright, singly pinnate colonies with monosiphonic or more rarely, in the basal part polysi- phonic stem. Hydrocaulus divided into internodia with one or several apophyses alternating to either 54 HYDROIDA II side. The apophyses have each an unbranched hydrocladium, divided by transverse joints into segments with numerous hydrothece. Each, or more rarely, every alternate internodium on the hydrocladium has on its distal half a hydrotheca entirely fused down its one side with the inter- nodium, or more rarely having a low free adcauline edge. The hydrotheca-bearing internodia are also distally furnished with a median pore, proximally with a median pore having raised edges, through 2 and '/s of that / which the naked sarcostyles pass. The length of the hydrotheca varies between ‘£/ of the internodium. The gonothece are situated on the stem or on the basal parts of the hydrocladia, without 200 m. Sous sce VOOR fasten tenes BOO CITI: t—- === 2000 Mm. Fig. XXIII. The distribution of Avrchenpaueria pinnata in the Northern Atlantic. In the hatched regions a common occurrence is stated by the literature. special protective organs. They are oval to pear-shaped, smooth or spiny, often much flattened from the side. / Forma ¢ypica. Short internodia with hydrothecz in length from '/; to '/, the internodium. Forma elegantula (G. O. Sars) slender internodia with small hydrothecz, length as a rule from '/, to '/s of the internodium. Material (forma /yfzca): Greenland? (without further details). The Faroe Islands: (without further details) |= Plwmularia echinulata Winther |. The synonymy of the species has recently been worked out by Bedot (1916). It gives us an interesting insight into the variability of a species, and throws a sharp light upon several of the HYDROIDA II On on distinguishing features which have hitherto been regarded as good specific characters in Plumularide. There are undoubtedly, among the numerous recorded species of Pluwmularia, synonyms in abundance, and the new species and varieties which are constantly being described do not make matters better. New forms demand not only morphological but also other justification, as is the case with the forms here noted. The variant group indicated as forma /yfzca penetrates exceptionally (Plumularia Hellert) right into the Mediterranean, but has otherwise its main distribution in the boreal waters and in sub- antarctic regions, thus exhibiting a tendency to bipolar occurrence (cf. Broch 1914). Forma elegantula on the other hand, which is remarkable for its fine slender build, predominates under tropical-subtro- pical conditions, and is only on rare occasions met with in the temperate seas. The area of distribution for Azrchenpauerta pinnata forma tyfica in northern waters coincides in the main with the fields on the chart (fig. XXIII); it is likely, however, that new finds will be made off the coast of Iceland, and we must wait until the species has been further localised in Green- land waters, before the query on the label can be erased. Azrchenpauerta pinnata appears in the northern waters as less susceptible to diminished salinity, and thus penetrates far up into the fjords; lower temperature, however, soon sets a limit to its progress. In the northern seas, it belongs to the littoral region, especially the upper half of the same, and only exceptionally occurs down in the abyssal. Gen. Plumularia (Lamarck). Upright, single or double pinnate colonies, the stem bearing on its apophyses undivided bran- ches (hydrocladia) with hydrothece unilaterally arranged, and partly or entirely fused with the branch. The apophyse lacks sessile large sarcothece; the sarcostyles are situated in two-chambered mobile sarcothecee, generally a pair at the mouth of each hydrotheca. Plumularia setacea (Linné) Lamarck. 1758 Sertularia setacea, Linné, Systema nature, ed. 10, p. 813. 1816 Plumularia setacea, Lamarck, Histoire naturelle, vol. 2, p. 129. * Single pinnate colonies with monosiphonic main stem. The stem is divided into short inter- nodia, each with a distal apophyse, turned alternately to either side. Each apophyse has a hydrocla- dium divided by transverse joints into internodia, of which latter every alternate one bears a hydro- theca and three sarcothece, and every other one or exceptionally two sarcothece in the median line; the hydrotheca-bearing internodium has a proximal, median sarcotheca, and a supracalycine pair at the opening of the hydrotheca. The length of the hydrotheca varies between '/, and '/; the length of the internodium. The hydrotheca is fused throughout its whole length with the hydrocladium. The gonothece arise from the branch apophyse on the stem. . They are elongated oval, with a cylindrical, narrow, often somewhat curved neck; the males are smaller than the females. The colon- ies are as a rule hermaphroditic, with the male gonangia on the basal part. Forma ¢yfica: length of hydrotheca '/,—"/; the length of the internodium; the internodia com- _ paratively coarsely built. 56 HYDROIDA II Forma mzcrotheca: length of hydrotheca '/,—'/; the length of the internodium; the internodia 5 of slender build. Material (forma ¢yfzca): “Thor” 35°57' N., 5°35 W., depth 740 metres Iceland: Vestman6, depth 50 fathoms. Plumularia setacea divides in the same manner as the foregoing into a widely distributed warm water variety, forma mzcrotheca, and a temperate forma /yp7ca, occurring both in subantarctic and boreal waters. Plumularia setacea is in northern waters a denizen of the middle and upper parts of the lit- 200 m. ~ esr eH ¢tooom, reafere nae s ase tai O OOrtT: Fig. XXIV. The occurrence of Plwmularia setacea in the Northern Atlantic. In the hatched parts the occurrence according to the literature is common, although scattered. toral region, whereas in warmer seas it goes fairly deep down into the abyssal region. The species is altogether somewhat rare in the boreal area (fig. XXIV) and penetrates in considerable numbers only into the southern and warmest parts of the same. Plumularia Catharina Johnston. 1833 Plumularia Catharina, Johnston, Ilustrations in british Zoology, p. 497, figs. 61—62. Upright, pinnate colonies with simple or branched, monosiphonic, little pronounced stem. The branches proceed from the base of the hydrothecee on the stem, and are as a rule placed oppositely, more rarely alternating. Stem and hydrocladia are divided into internodia by alternating transverse HYDROIDA II 57 and oblique nodes; above a transverse joint there is an internodium bearing one or two unpaired sarcothecze in the median line, then the highly oblique joint, and an internodium furnished with a proximal, unpaired median sarcotheca, a large hydrotheca, and two supracalycine pairs of sarco- thecee. Of the supracalycine pairs of nematothecz, the outermost is placed on small projecting apo- physes, the inner pair arises from the internodium on the inner side of these sarcotheca apophyses. All the sarcothecee are mobile. The hydrotheca is very slightly fused with the internodium, the adcladial side has a free portion, in length equal to the hydrotheca opening or a little less, between ‘/, and 3/, the length of the hydrotheca. The hydrotheca is somewhat expanded towards the opening, and is able to accomodate the contracted polyp almost entirely. The gonothece arise from the stem or the hydrocladia close beneath the hydrothecee. The gonotheca is oval to pear- shaped, as a rule somewhat curved, the males a little more slender than the females. The female gonothece have basally two sarcothecze, which, (according to Hincks) are lacking in the males. A ; Material: The Faroe Islands: 6 miles N. by W. of Store Kalso depth 60 fathoms Deep hole at the north point of Nols6, — 100 — Bor6nees 13 miles in N. 75 W. — 30 — a Fig. XXV. Plumularia Catharina The inner pair of supracalycine sarcothecee in Plumu- from 6 miles N. by W. of Store Kalsé. a. hydrothecate internode seen from behind. — 4. two successive inter_ tion of most investigators; it is probably this pair of sarcothecze nodes in side view. — 7 inner pair of supracalycine sarcothecze. (> 80). laria Catharina (fig. XXV) appears to have escaped the atten- which has given rise to the distal median sarcotheca so often ascribed to the species. Such median (unpaired) distal sarcothecze I have been unable to find in the colonies at my disposal; not infrequently, however, one or both of the sypracalycine may have fallen away, rendering it difficult even to trace where they had been. It is remarkable that it should be the inner pair which exhibits such a marked tendency to fall off, exceeding that of the other sarcothecze; the ones in question are, how- ever, also the smallest. In view of the abundance of the present material, and the fact that I found occasion also to investigate material from other parts of the Atlantic, we must regard the statements as to occurrence of an unpaired distal sarcotheca on the hydrotheca-bearing internodium in /Plwmz- laria Catharina as based on incorrect interpretation of the inner pair of supracalycine sarcothece. There can be no doubt that the species Plumularia geminata Allman, Plumularia alternata Nutting and Plumutaria Clarket Nutting should be included under Plumularia Catharina, as | have already pointed out in a previous work (I912 p. 4); it is impossible to attach any weight to the characters given for specific distinction when once a larger material has been closely investigated. Plumutaria Catharina is a southern visitor to the boreal waters (fig. XX VI); round the British Isles it still seems to be of fairly frequent occurrence, but off the coast of Norway it is but little met with, and has only once been recorded from the south coast of Iceland. At the Faroe Islands, the The Ingolf-Expedition. V. 7. 8 <8 HYDROIDA II RaWechranencisan axe 200 m. See See VOOiaA Ppa OOM Tibho ese POEM ab Fig. XXVI. The distribution of Plimularia Catharina in the Northern Atlantic. In the hatched parts the literature notes a common, although scattered occurrence. species seems to be somewhat more common than would appear from earlier records; at the two loca- lities noted here, it was present in great numbers. In Greenland waters, Plwmularia Catharina has not yet been found. It belongs especially to the upper half of the littoral region. Gen. Polyplumaria’ G. O. Sars. Upright, composite pinnate colonies with polysiphonic branched stem. The apophyses of the stem (the primary tube) bear hydrocladia from which secondary hydrocladia proceed, as a rule from the first hydrotheca-bearing internodium. The apophyse lacks sessile sarcotheca. All the sarcothecz are mobile and two-chambered. It is not without hesitation that I retain this genus beside Plamadlaria, with which it is closely related; it may be a question whether we should here, more than in other cases, base the generic division upon the form of ramification. That I have retained it for the present as a separate genus is due to the fact that its species, from their peculiar appearance, form a well-defined group, sharply distinguished from the remaining ones which have been included in the genus Plumularia. My material is not so extensive as to suffice for a revision of the entire family, a task which becomes more and more imperative as further species continue to appear in the literature. A work such as ' Nutting has (1goo p. 83) by a slip of the pen called the genus Polyplumularia. HYDROIDA II 59 that of Nutting (1900) shows more than most how absolutely indispensable such critical revision really is. It is therefore most correct here for the present to retain a genus such as Polyplumaria. Polyplumaria frutescens (Ellis et Solander). 1786 Sertularia frutescens, Ellis and Solander, The natural history of many curious and uncommon Zoophytes, p. 55, pl. 6, fig. a, A, pl. 9, fig. 1. The colonies are upright and singly or doubly pinnate, with polysiphonic hydrocaulus. The primary stem tube bears on its front a series of hydrothecz, one to three on each internodium; at the base of each hydrotheca, the tube has an apophyse, which is directed obliquely forward and to the side, alternating to either edge. The apophyse bears a hydrocladium, as a rule secondarily branched, which is at first directed obliquely upward and forward, but gradually turns into the broad plane of the colony. The hydrocladium is divided by transverse nodes into internodia, bearing one to several hydrothecze, and around this a pair of supracalycine sarcothece, and one median, unpaired, under. the base of the hydrotheca. The hydrotheca is fairly large, slender, and fused throughout the whole of one side with the internodium. ‘The secondary hydrocladia proceed from under the base of the basal hydrotheca of the primary hydrocladia, and assume the same appearance as the primary hydrocladia. The gonothece are set on the branches without special protective organs. They are pear- shaped, cut off obliquely distally, with a large lid-bearing opening. Material: “Ingolf’ St. 54 63°08’ N., 15°40’ W., depth 691 fathoms 3,9” = = &5 (gen IN, ueee WG — 316 _ 59° The Faroe Islands: 61°40’ N., 7°40. W.. — 135 = 16 miles E. by S. of the south point of Nols6, depth 80 fathoms. Polyplumaria frutescens has its chief occurrence in the lower parts of the littoral region, and in the upper portion of the abyssal. It is a southern visitor to the boreal seas, having only on a single occasion been encountered in colder water layers, viz. east of Iceland (fig. XXVH). In Green- land ,waters, the species has not yet been found, and its occurrence at the Faroe Islands is here recorded for the first time. Polyplumaria flabellata G. O. Sars. 1874 Polyplumaria flabellata, G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 93, pl. 2, figs. 16—22. Upright, doubly pinnate colonies with polysiphonic branched main stem. The primary tube bears on its internodia alternating apophyses, directed obliquely forward and upward. From the apo- physe proceed the primary hydrocladia, which soon curve into the broad plane. The hydrocladia are divided by almost transverse nodes into internodia, each bearing a large hydrotheca, a pair of supra- calycine sarcothece, a larger, unpaired proximal, and a smaller unpaired distal sarcotheca in the median line. The hydrothece are fairly large, about half as long as the internodium; the adcauline wall has a free portion in length about equal to the opening diameter, between one and two thirds of the length 8* 60 HYDROIDA II 200 mM. Speco os YOO meee, 1000 Mm, on eee eee 2000m. Fig. XXVII. Localities of Polyplumaria frutescens in the Northern Atlantic. In the hatched parts the literature notes a scattered occurence without further data. of the hydrotheca. The secondary hydrocladium proceeds from beside the basal hydrotheca of the primary hydrocladium, and is of the same appearance as this. The gonothecz are fastened to the stem or the branch apophyses by a very short stalk. They are oval, with a large, somewhat asymmetrical distal opening, and with four sarcothece at the base. Material: “Thor” 35°57’ N., 5°35’ W., depth 740 metres Iceland: Vestman6, — 510 — According to Ritchie (1911 p. 223) the number of unpaired small distal sarcothecee on the internodium should vary from one to three. No such variation could be discerned in the colonies investigated by me. Polyplumaria flabellata is a very rare visitor in the northern waters (fig. XXVIII) and occurs here only in the deeper water layers. The species has altogether its main distribution in the upper parts of the abyssal region. The Vestmanna Islands mark the most northerly point where it has been found up to now; in Greenland waters it would seem to be entirely lacking. Polyplumaria profunda (Nutting). 1900 Plumularia profunda, Nutting, Plumularidae, p. 66, pl. 8, figs. 2-3. Upright, composite pinnate colonies with branched polysiphonic main stem. The primary tube which is seen in the outer parts of the colony is divided by transverse nodes into internodia, bearing HYDROIDA II 61 ceoonmenacct OC) fe SS 600 m. wae ee ee eee m900m, Serr ns Or Fig. XXVIII. Finds of Polyplwmaria flabellata in the Northern Atlantic. one or two alternating apophyses. The apophyse proceeds asymmetrically from the base of a cauline hydrotheca; this is surrounded by a pair of supracalycine sarcothecze, and a third sarcotheca situate proximally and a little to the side of the median line, somewhat removed from the base of the hydro- theca, on the side of the median line opposite to the apophyse. The hydrocladia are divided by trans- verse nodes into internodia, which have about the middle a hydrotheca with a supracalycine pair of sarcothecze, on low apophyses near the opening of the hydrotheca, and a proximal, unpaired sarcotheca in the median line near the proximal end of the internodium. The basal internodium on the primary hydrocladium has two proximal unpaired sarcothecee in the median line; at the base of this inter- nodium’s hydrotheca there appear, in fertile colonies, apophyses to the secondary hydrocladium, which is of the same structure as the primary. The hydrothece are on the hydrocladium about twice as long as broad; on the stem somewhat shorter; they have a somewhat outward curving opening margin, and are fused throughout their whole length with the internodium. The gonothece are situate on the stem or close under the base of the proximal hydrothece on the primary and secondary hydrocladia; they have a short, often rudimentary stalk. The gonothecz are pear-shaped, often curved, rounded off somewhat asymmetrically distally, with a broad opening; they have two sarcothecz basally. Material: “Ingolf? St. 24 63°06’ N., 56°00’ W., depth r199 fathoms 2,4° po =~ i (ogee? INES sade Wie — 316 — 59° ° — = QSOS cao: INE 20927) W., — = 59° 62 HYDROIDA II That Nutting (1goo p. 66) should refer this species to Plemularia must be due to his having had small or poorly developed colonies to deal with. From the “Ingolf” St. 55 we have a couple of splendid colonies showing the typical secondary hydrocladia of Polypimaria in practically every branch, and richly furnished with gonangia. These are situated on the basal part of the hydrocladia — both primary and secondary, and partly also on the tubes of the stem. It might be imagined that the present specimens, with their typical Polyplumaria colonies, were specifically different from Nutting’s Plumularia profunda. We found, however, besides the two mentioned, extremely luxuriant colonies, also a smaller, single !| pinnate colony, where only the basal hydrocladia were furnished | with secondary hydrocladia, all the remaining hydrocladia being simple. Nevertheless, this colony is likewise fertile, and a fur- ther investigation of the larger colonies shows that here also the secondary hydrocladia are lacking on several branches. In all these colonies, the stem is polysiphonic. But from the “In- golf? St. 24 we have a quite young, sterile colony, where the whole stem is monosiphonic; only at the bottom of the basal part is a secondary tube developed. Here then, we have the / ‘| complete transition from Nutting’s description to the typical | FI Polyplumaria which the species represents in its fully developed 7 form. The resemblance in detail will furthermore be seen from = a a comparison of the illustrations here given (fig. XXIX). The finding of Polyplumaria profunda in the northern Atlantic is highly interesting. The species is a typical deep sea a Fig. XXIX. b Polyplumaria profunda “Ingolf’ St. 24. a. Hydrocladial internodium. 4. Internodium find, that it penetrates in deep water right up into Davis Strait of the primary stem tube, with apophyse. (X 60). form, previously known only from West Indian waters. We now and Danmark Strait, and to the southern slope of the Iceland region, where the warm and salt Atlantic water predominates. It is evidently not able to pass over the submarine ridges or into strictly boreal waters. Nemertesia Lamouroux. Upright colonies with as a rule pronounced main stem, which may be branched or un- branched, generally articulated and furnished with strong apophyses bearing finely built hydro- cladia. The hydrocladia are single, unbranched. The colonies are furnished with stalked, two-chamb- ered and mobile sarcothecee, and have in addition, on each apophyse at its upper side where it pro- ceeds from the stem, a large sessile sarcotheca (“mamelon”). The hydrocladia are segmented, and have several hydrothece, which as a rule are fused throughout their entire length with the branch. The hydrocladia are generally situated in several rows in fully developed colonies. Formerly, in drawing the limits for this genus, the principal stress was laid on the fact that the hydrocladia are in multiserial arrangement, not merely in two rows as in Plawmularia. This cannot HYDROIDA II : 63 however, be admitted as a particularly important feature in generic distinction, as will be seen from a closer study of the Memertesia species and their development. A species such as Vemertesia tetrasticha (Meneghini) differs in reality but little from the pure P/wmularia type, its four-rowed appearance being due to a slight alternating displacement of the apophyses on the two sides; we have here then, as a matter of fact, two-rowed colonies, which have probably when younger been of the pure Plwmdlarza form. In Nemertesia ramosa (Iamarck) I have in a previous work (1912 p. 5) pointed out that the distal parts of the colony not infrequently exhibit a purely biserial arrangement of the hydrocladia; the present material shows that small colonies both of this species and of Nemertesta antennina (LAnné) are altogether biserial. Here, as a matter of fact, it is quite another character which warrants the generic identity, to wit, the large sessile sarcotheca (“mamelon”) of the apophyse, which occurs in the colonies from the earliest stages onwards. : The development of the colonies, and the grown colonies themselves, clearly show that the multiserial arrangement of the hydrocladia is a secondary adaptation which is, moreover, in many species, subject to great variation within one and the same colony. The number of branch series is even variable in the single species, as in Nemertesta ramosa, where it varies from two to eight, or Nemertesia antennina, where we find from four to twelve. It is not easy to see why it should be more reasonable and effective to draw the limit between biserial and multiserial than for instance be- tween quadriserial and multiserial. On the other hand, there is one constant feature in all the species hitherto noted under this genus; to wit, a peculiar large sessile sarcotheca on the apophyse. A com- parison with other species (see for instance more particularly Aglaophenopsis cornuta) suggests that this formation should in reality be regarded as an abortive hydrotheca. In most cases, it forms a rounded raised portion, with circular opening, happily described by the French writers as a “mamelon”. This sarcotheca occurs in colonies from the smallest to the largest in the same manner, whether the species is biserial or multiserial. It must thus be regarded as of generic importance. Consequently, we must reject from P/wmularia those species which are furnished with a “mamelon” on the apophyse and have unbranched hydrocladia, placing them instead under Memertesva. We thus obtain, in this genus, biserial and multiserial forms. It is impossible to determine, from the data available, whether a species like Memertesia caulitheca (Fewkes) (= Plumularia caul- theca, Nutting 1900 p. 63) is a young stage or not; its gonangia have not yet been discovered, and it may possibly be found to go through a development similar to that of onr northern species, passing gradually from a biserial type over into the multiserial form. If not, then it must be regarded as a primitive species. The next stage is represented by Memertesia tetrasticha (Meneghini), with its alter- nately displaced apophyses in the two branch rows; Nemertesia ramosa undergoes this stage, and probably also Wemertesia antennina, the former, however, at any rate soon proceeding further with a marked twist of the internodia, so that the apophyses in one internodium are perpendicular to those of the previous and subsequent ones. Not until later do further apophyses appear at the same level as the first, and from now onwards we regularly find, owing to the revolved position, a number of branch series divisible by two. The nature of the stem has also served as basis for a division of the genus; here again, how- ever, there is no real difference of principle to work on. The younger stages of Memertesia ramosa 64 HYDROIDA II have monosiphonic stem; not until later does it become canaliculate, and finally, in fully developed colonies, we find purely polysiphonic basal parts of the stem, where secondary tubes cover the canali- culate central tube. Thus the limits between Memertesia and Antennopsis become effaced, and these genera must in consequence, as I have previously maintained (1912 p. 28), and as Stechow also points out (1913 p. 25) be united into one. Similarly it follows, that Stechow is correct in placing Svbogella under Nemertesia. Bedot, in a work which has just appeared (1917) treats of the genus NMemertesia at length, unfortunately, however, without giving any synopsis of the generic characters. It is nevertheless clear that Bedot inclines to regard the canaliculate (“pluricanaliculée”) stem as a family trait. The char- acter is developed, as mentioned above, only in somewhat larger colonies — generally at least 5 cm high — it is moreover often lacking in large distal parts of the colony in the northern species, where the stem fre- quently retains its primary (“unicanaliculée”) character. And finally, the primary “pluricanaliculée” stem tube is secondarily covered, as in Nemertesta ramosa, by tubes “unicanaliculées” to a greater or lesser extent. This in itself detracts from the value of the character in question. But in addition, it is also found to stand in a certain relation to the dimensions of the stem tube; thick, single stems are “pluricanaliculées” in spe- y ) c=) 2 cies within the same genus, where the thin ones are — constantly “unicanaliculées” (cf. for instance Z2dularia). As a matter of fact, the two types “fasciculée” (poly- ; , siphonic) and “pluricanaliculée” (canaliculate) represent Fig. XXX a—c. Nemertesia antennina, juv. “Ingolf’ St.98. parallel processes of development towards the same a. The entire colony (nat. size). d. Internodium of the al Ards as 1 wellare: igablette Mtl mthemeocnres hydrocaulus with the hydrocladial apophyse, showing the sessile sarcotheca. — c. Two successive internodes of a as basis for generic distinction, so also the latter hydrocladium (# and c & 8o). 4 , : character must. be considered quite inadequate as a means of distinguishing between genera (or families). Nemertesia antennina (Linné) Lamouroux. 1758 Sertularia antennina, Linné, Systema nature, ed. 10, p. 811. 1812 Nemertesta antennina, Lamouroux, Extrait dun mémoire sur la classification des polypes coralli- génes, p. 184. Colonies with unbranched or quite exceptionally slightly branched canaliculate and segmented stems. The apophyses are set in circles on the internodium, each circle containing three to six or even more apophyses; the internodia are revolved, so that the stem has twice the number of longitu- dinal rows of apophyses. Near its point of origin, the apophyse has on its upper side a comparatively small, sessile sarcotheca (“mamelon”) and two or three irregularly arranged, stalked and two-chambered HYDROIDA II 65 mobile sarcothece. The hydrocladia are divided by transverse nodes into internodia of which normally every second one bears one or two unpaired sarcothece in the median line, the alternate ones having a small hydrotheca with a supracalycine pair of sarcothecee at the mouth, and an unpaired median sar- cotheca on the proximal part of the internodium. The hydrotheca is about '/; to '/; the length of the internodium, and is on one side entirely fused therewith. The gonothecz are attached by an almost rudimentary stalk to the apophyses; they are oval to pear-shaped, with a distally laterally placed asymmetrical opening. aes mes scans looom. aneetde mates eben e 2 OOLITI a Casiikraroissrvenst OONTMie we OO) Vissi. cone 600m. Oo Fig. XXXI. The distribution of Nemertesia antennina in the Northern Atlantic. In the hatched parts the literature notes a scattered although common occurrence. / Material: “Ingolf” St. 87, 65°02,3' N., 23°56,2’ W.; depth 110 fathoms — = OF, (oul ING eeese7 \iVee — 976 — ye o EOS O5e38) 9 New 262277 Wi: — 138 — Op Greenland: Davis Strait, = = (without further details) See OS C7 a 5445 Wi O78 Iceland: 5 miles E. of Seydisfjord, — 135 _ The Faroe Islands: Deep hole at the north point of Nolsé, depth roo fathoms. Some luxuriant colonies from Davis Strait exhibit interesting variations in the number of hydrocladia. The nodes of the stem are slightly marked, and each internodium bears but three apo- physes; owing to the revolution of the internodia therefore, these colonies or parts of colonies are six- rowed; among these colonies again there are others, or in the single colony, other parts, which in a 9 The Ingolf-Expedition. Y. 7. 66 HYDROIDA II similar manner appear eight-rowed, with four apophyses in the circle. The same octoserial type was met with at the “Ingolf” St. 87, and from St. 92, we have for the first time specimens with six apo- physes in each circle, giving a twelve-rowed colony. The revolution of the segments is thus charact- eristic of grown colonies, and calls to mind the features noted in Memertesia ramosa (cf. Broch 1912 p. 5). From St. 98, the “Ingolf’ brought a young specimen of Memertesia antennina which is of con- siderable interest (fig. XXX). The colony is still quite biserial, and can only be distinguished from Plumularia by the sessile “mamelon” of the apophyses. As however, the arrangement of the sarco- thecee and hydrothece entirely agrees with Memertesia antennina, | have no hesitation in referring the colony to this species, the more so since altogether parallel stages occur in the following species together with later phases of development. Nemertesia antennina is a southern form with wide distribution in the boreal region (fig. XXXI). Towards the south, it goes at any rate as far as Madeira, and is common in the Mediterranean; it belongs to the middle and lower parts of the littoral region, but may exceptionally, as shown by the finds from the “Ingolf” St. 92, go deep down into the abyssal. It has not yet been met with in purely arctic waters, unless the one find from the east coast of Iceland should be so described. Nemertesia ramosa Lamouroux. 1816 Memertesia ramosa, Lamouroux, Histoire des Polypiers coralligénes, p. 164. 1903 Antennularia vartabilis, Broch, Die von dem norwegischen Fischereidampfer “Michael Sars”..... gesammelten Hydroiden, p. 10, Taf. IV, figs. 22—25. Colonies with branched main stems, polysiphonic in their lower parts, canaliculate in the upper. Apophyses form circles about the internodia of the stem, two to four in each circle, and the internodia are revolved, giving twice the number of longitudinal rows. In the lower parts of the colonies, where secondary tubes cover the primary stem, the circular arrangement of the branches is less distinctly marked. The apophyse has on its upper side a strong, narrow, but high sessile sarcotheca (“mamelon”) and 3—4 irregularly placed, mobile sarcothecee. The hydrocladia are divided by transverse nodes into internodia, each of which has a median hydrotheca with a supracalycine pair of sarcothece at the opening, and one proximal and one distal unpaired sarcotheca in the median line; exceptionally, the distal part with its sarcotheca may be divided by a slight joint’ from the main internodium. The hy- drotheca is entirely fused with the hydrocladium, and is '/s to '/, the length of the internodium. The gonothece are attached to the apophyse by a short, almost rudimentary stalk. They are oval to pear-shaped, with a distally lateral asymmetrical opening. Material : “Ingolf” St. 55 63°33’ N., 15°02’ W.; depth 316 fathoms, 5,9 _ =r Ss Osean NA 25c2m Wa, -—— 170 _ PRO Gres SNi, 19235) Was — 872 metres Iceland: Vestman6, — 50 fathoms The Faroe Islands: 62°16’ N., 6°06’ W.; — 110 metres 60°55’ N., 8°56’ W.; — 840 — HYDROIDA II 67 6 miles N. by W. of Store Kalso, depth 60 fathoms Deep hole at the north point of Nolso, — 100 _ I,5—2 miles off the mouth of Borévig, — 20-30 — Prévenzes 13 miles in N.75°W., — 30 — Borénes in N.75°W., — 30 - The Faroe Islands, == 566) = ras Nemertesia ramosa is extremely variable as regards arrangement and number of the hydrocladia, as I have previously (1912 p. 5) had occasion to explain. In the revolution of the internodia, however, it follows the same regular principles as NMemertesia antennina. The structure of the stem presents c e Fig. XXXII. Memertesia ramosa juy. a. Young colony from “Ingolf’ St. 55 (nat. size). 6. hydrocladial internode from the same colony (> 80). c.. apophyse from the same colony ( 80). d@. colony from “Ingolf’ St. 85 (nat. size). ¢. apo- é physe from the colony from St. 85 (x 80). features of considerable interest. The distal part of its ramifications exhibits the same structure as Nemertesia antennina, having, inside the homogeneous peridermal chitinous sheath, coenosarc strings; these parts of the stem are thus canaliculate. Farther down, however, we find secondary tubes closely arranged about the primary stem tube, and the nearer we come to the base, the closer is the network and the thicker the stem. Where these secondary tubes occur, they cover the apophyses more and more, finally burying them altogether, while the hydrocladia here also fall away. Consequently, the basal part of well-developed colonies of Nemertesta ramosa lacks hydrocladia, whereby the colony assumes a highly peculiar appearance. At a couple of the “Ingolf” stations, some quite small colonies of Memertesia ramosa were found; these serve well to show the difficulty of distinguishing the young stages from Pluwmularia (fig. XXXII). The smallest colony (a) is altogether pinnate; the thin stem is divided into irregular internodia with a varying number of apophyses, but closer investigation shows that the apophyses do not form two regular longitudinal rows, being as a matter of fact alternately somewhat displaced to one side or the other, so that we have here a slight approach to quadriserial arrangement. A some- what larger colony (¢), where the stem is slightly thicker, reveals more clearly the displacement of * 9 68 HYDROIDA II the apophyses, which is here evident at the first glance. In this case, it would scarcely be possible for anyone to doubt that the specimen is a young Nemerfesia, the more so since the stem is strikingly thick. Further confirmation is in both instances afforded by the branch apophyses (c and ¢); in both colonies we find the characteristic “mamelon” on the upper side of the apophyse, close to the stem, which proves that they belong to the Nemertesia. The entire arrangement of the hydrothecee and sarcothecz also shows that the species is Memertesta ramosa. The stages found already show that the younger Nemertesia are throughout constructed after the Plumularia type, with biserial apophyses, and that Nemertesia must be derived from Plumularia. It would further seem to suggest that Pluwmularia caulitheca Fewkes is probably a young stage of a 200 m. eS OCHS sarderecertehOOONI) 9. 0) ees eens 2000m. Fig. XXXIII. Occurence of Memertesta ramosa in the Northern Atlantic. In the hatched region the literature notes a conimon occurrence. Nemertesia. And it is likely that also other Plumularia species in reality cover young Nemertesia species, and should, from the presence of a “mamelon”, be transferred to that genus. Among the synonyms of Memertesia ramosa should also be reckoned Antennularia variabilis Broch. The defective specimens, where only the chitinous parts are preserved, have lost all their sarcothecee, so that only a hole in the periderm, or a slightly raised part here and there, shows where the sarcothecee have been. The difficulty of discerning these remains has led to their being regarded as variable in number, and the remains or traces of supracalycine sarcotheczee had altogether escaped attention. Otherwise the colonies agree entirely with Nemertesia ramosa, and must thus be referred to that species. Nemertesia ramosa has its chief occurrence in the littoral region, especially in the middle and HYDROIDA II 69 lower parts of the same; it has been met with once or twice quite deep down in the abyssal region, as for instance on the “Thor” expedition, when it was taken near the Faroe Islands at 872 metres, probably the greatest depth from which the species has hitherto been recorded. Nemertesia ramosa belongs to the warmer parts of the Atlantic, and penetrates thence (fig. XXXIII) in great numbers into the southern part of the boreal region. The species has not hitherto been found in Greenland waters, but is recorded fiom one or two places on the south coast of Iceland. Round the Faroe Is- lands, it is seen to be of very frequent occurrence, and is said by Hincks (1868 p. 283) to be more numerous even than Nemertesta antennina on the coasts of Scotland. The species has not yet been located with certainty on the Norwegian coasts, but its occurrence in the Skagerak (Broch 1905 p. 24) and Bohuslan (Jiderholm 1909 p. 105) suggests that it will probably be found to occur there! Polynemertesia nov. gen. Upright colonies with distinct, branched main stem, exhibiting segmentation in its monosipho- nic parts; the stem is furnished with alternating strong apophyses which bear finely built hydrocladia. The hydrocladia are secondarily branched. The apophyses — both those of the primary and those of the secondary hydrocladia — are furnished on their upper side, near the point of origin, with a short sessile sarcotheca, “mamelon”; all the remaining sarcothecee are mobile. The primary and se- condary hydrocladia are segmented, and bear several hydrothecee, which are as a rule fused through- out their entire length with the branch. It is with considerable hesitation that I have established this new genus for Plumularia gra- cillima G. O. Sars. Previous investigators have overlooked the presence of a “mamelon” on the apo- physes, in virtue of which the species must be separated from the Plwmaularia. With its secondary ramification of the hydrocladia, however, the species stands in the same relation to Nemertesia as Polyplumaria to Plumularia. A separation of the two latter genera therefore logically demands a like separation between the parallel groups of Memertesia and Polynemertesia. The fact that the prim- ary apophyses in the only known species are biserially arranged on the hydrocaulus must be regarded as of minor importance. ) ’ It might be thought more reasonable here to revive an older name for the genus in question; it should then be Dzplopteron or Schizgotricha. The former, however, has already been withdrawn by Allmann himself (1883 p. 30) as synonymous with Polyplumaria; Nutting’s attempt to revive it (1900 p. 81) can only be explained as due to his having taken as basis for the generic division a character which should otherwise be used only with caution even in distinction between species, as in all pro- bability, it would seem that the type species for Polyplumaria and Diplopteron are very nearly identi- cal. And with regard to Schzzofricha it should be borne in mind that both the two species originally placed by Allman (1883 p. 28) in this genus must be referred to Polyflwmaria. It would thus be incorrect to take as the type a species which has not from the first been ascribed to this genus; Plz- mularia gracillima G. O. Sars is first placed under this head by Nutting (1900 p. 80). Of the remain- ing species which have been referred to this genus, Schizotricha bifurca Hartlaub and Schizotricha 1 After the close of the manuscript a find of the species in the Trondhjem fjord has proved the correctnes of this supposition. 7O HYDROIDA II antarctica Jaderholm must doubtless be removed to a genus of their own, more closely related to Kirchenpaueria. It would thus not be advisable to introduce a new diagnosis for Schizotricha; the genus should rather be allowed to disappear definitely as synonymous with Polyflumaria, which latter generic appellation is older, and originally better defined. For Plumularia gracillima G. O. Sars there- fore, it will be best to take an entirely new generic name. Polynemertesia gracillima (G. O. Sars). 1873, Plumularia gracillima, G. O. Sars, Bidrag til Kundskaben om Dyrelivet paa vore Havbanker, p. 86. 1893 Plumularia groenlandica, Levinsen, Meduser, Ctenophorer og Hydroider, p. 63, tab. VIII, figs. ro—r1a2. Single pinnate colonies with monosiphonic or in the basal parts polysiphonic main stem. The mono- siphonic stem is divided by trans- verse nodes into internodia, which bear distally a short apophyse, di- rected obliquely forward, turning alternately to either side of the me- dian line. The stem has no hydro- thecze, but bears mobile sarcothece, two unpaired, somewhat asymme- trically arranged on the basal part of each internodium. The apophyse has a “mamelon” on its upper side near the stem; beside this on the rear side a mobile sarcotheca, and b c a Fig. XXXIV. Polynemertesia gracillima from the Davis Strait also an unpaired mobile sarcotheca |type specimen of Phumularia groenlandica|. a. Internodium of the stem with primary apophyse. %. Second internode of a prim- ary hydrocladium with secondary apophyse, showing a distinct apophyse bears a secondarily bran- “mamelon’”. c. Hydrothecate internode. ( 80). distally in the median line. The ched hydrocladium; the hydrocla- dium is divided by transverse nodes into irregular internodia, of which every alternate one bears two unpaired sarcothecz in the median line, every other a median hydrotheca, a supracalycine pair of sar- cothecee at the opening of the same, and an unpaired proximal, and as arule an unpaired distal sarco- theca in the median line; on the distal parts of the hydrocladia the hydrothecaless internodium often melts into the hydrotheca-bearing internodium. The basal internodium of the hydrocladium is hydro- theca-bearing; the following small internodium is furnished at the middle with an apophyse directed obliquely forward and bearing the secondary hydrocladium; from the second segment of the latter there proceeds as a rule a further hydrocladium in the same manner; these secondary (tertiary) apophyses also are provided with a “mamelon” and two mobile sarcothece, as in the case of the primary apo- physe. The secondary hydrocladia are of the same structure as the primary. The hydrothece are small, with slightly outward curving opening margin, and are throughout their entire length fused with the internodium. HYDROIDA II 71 The gonothece are attached to the apophyse beside the sessile sarcotheca. Fully grown gon- angia have not yet been found. Material: “Ingolf” St. 27 64°54’ N., 55°10’ W., depth 393 fathoms 3,8° = eu, Rey sayy) Ni) SC Greenland: Davis Strait (without further details) [type specimens of Phumularia groenlandica\. Iceland: Ingolfshéfdi 9'/, miles in N. by E.1/, E., depth 53 fathoms. Levinsen (1893 p. 63) gives a very detailed description of this species, which he incorrectly regards as different from Sars’s Plumularia gracillima. He has however, in common with others who SBOE SS ooe Gloom 0 ere fooom. eases ener ee OOM: Fig. XXXV. The localities of Polynemertesia gracillima in the Northern Atlantic. In the hatched region the occurrence according to the literature is common, although scattered. have investigated the species, overlooked its typical sessile sarcotheca on the apophyses (fig. XXXIV) It is noticeable that a mamelon occurs not only on the primary but on all the apophyses in the colony. The idea that it should, as Nutting (1900) believes to be the case with other species, form the point of origin of the gonothece, is due to inadequate investigation; the gonothecee have their point of attachment by the side of this sarcotheca. Levinsen’s description incorrectly gives the impression that he has had grown gonothecz before him at the time; they are, however, only quite young stages, and grown gonangia have thus not been described for this species. Polynemertesia gracillima is plainly a southern visitor to the northern waters, and has strangely enough not yet been recorded in the British waters (fig. XXXV). The “Ingolf” was able to furnish 72 HYDROIDA II further data as to the occurrence of the species at West Greenland, where it penetrates right into the lille Hellefiskebanke. On a single occasion it has been found in Iceland waters. On the coast of Norway it has been met with now and then between Lofoten and Stavanger. It has also been found off Bohuslan (Jaderholm 1g09 p. 108). The species belongs to the lower part of the littoral region, and the upper parts of the abyssal. Family Aglaophentide. The hydrothecze are large, with distinctly bilateral structure, sessile, and with the one side wholly or partly fused with the branches. The diaphragma is assymmetrical or bipartite. The polyps can retire altogether into the hydrothecee. The sarcothecee are sessile, immobile and well developed; exceptionally we may find, in addition, also mobile, stalked supracalycine sarcothecze. The hydrotheca margin is as a rule furnished with teeth. The colonies are monopodial with terminal growth point. The endoderm of the polyps is divided into a fore-stomach and a digestive part; the ectoderm often gives off an ectoderm lamella which fastens the polyp to the ribs of the hydrotheca. The division of this family is based chiefly upon the nature of the gonangia and the protective formations which are richly and variously developed in the different genera. Primitive in this respect is Halicornaria, from which the remainder are derived. On the one side, there is a development to- wards Mematocarpus, where the hydrocladia are secondarily branched, though without discernible relation to the gonangia. On the other arise, in all probability separately, the phylactogonia-bearing genera Avlacphenopsis and Cladocarpus, typical deep sea genera, of which the former has hydrotheca- bearing phylactogonia, the latter, on the other hand, only sarcotheca-bearing phylactogonia. Possibly also, the corbula-bearing genera Thecocarpus and Aglaophenia should be derived from these, but their origin is not yet certain. Gen. Halicornaria (Busk). Upright colonies with branched or unbranched main stem, the apophyses of which bear un- branched hydrocladia with several hydrothecee. All sarcothece are immobile. The gonangia are situate on the stem or branches without protective organs of any kind. . Halicornaria campanulata (Ritchie). 1912 Cladocarpus |?) campanulatus, Ritchie, Some Northern Hydroid Zoophytes, p. 226. The colony is doubly pinnate, with polysiphonic branched main stem, which consists in its extreme portions of the primary segmented tube alone. This has internodia of medium length, which bear about the middle a short, but quite broad apophyse; the internodium is further provided with a pair of sarcothecee at the upper side of the apophyse, and an unpaired median sarcotheca in front at its lower side; the sarcothecee are almost tubulous, adcaulinally split. The hydrocladia have on each internodium a broad, and not particularly large hydrotheca and three sarcothecze; a supracalycine pair at the opening, and a median proximally, which with its opening margin reaches up to the bottom HYDROIDA II “I ios) of the hydrotheca. All the sarcothecee are adcaulinally split, and have a slightly dentate margin. The hydrotheca is broad, and has a very slightly curved opening margin; its basal part has a somewhat thicker wall than the distal two-thirds, and the boundary between the two portions is apparent as a fine line abcladially directed obliquely forward towards the opening; hydrothecal ribs or septa lacking. The internodium shows two to four inner ribs at the adcladial side of the hydrotheca; one such, which is three-branched, and markedly prominent, forms a boundary between the proximal sarcotheca and the internodium. The gonothecz’ are situate on the stem at the apophyses. The young gonotheca shows distally a peculiar oblique termination, the one side of which gradually projects further forward, suggesting that the fully developed gonotheca would be furnished with a roof-like upper lip. Phylactogonia lacking. Material: “Ingolf”? St. 127 66°33' N., 20°05’ W., depth 44 fathoms, 5,6° Vicelandzristiltjord 662430 Ne rac53a; We, —. 378) — Ritchie (1912 p. 226) refers this species to Cladocarpus, but with a query, as he did not find gonangia in his specimens. These agree entirely with the present colonies (fig. XXXVI) which, from the comparatively short, broad hydrothecze, can hardly be ey confused with other species from northern waters. The col- Cae ste onies in question show that the species should be placed / under Halicornaria. The gonangia occur in several stages of ‘i ae development, but none fully developed. ‘The series ot phases ‘ ee / / represented in the colonies investigated are entirely parallel “\ it yy \ ee : to what we find in Cladocarpus imteger (G. O. Sars); the oldest stage also seems to show that it developes, as does the species mentioned, an “upper lip” which will dome out a. Fig XXXVI. Halcornaria campanulata from “In- golf’ St. 127. Hydrothecate internodium from a determine, how far the development proceeds. hydrocladium in side and front view. ( 60). more or less over the opening; further investigations must ' Phylactogonia are altogether lacking in the colonies here concerned, and the species must consequently be regarded as a Halicornaria; there is, however, the possibility that it may later prove to be a primitive Cladocarpus. The otherwise close resemblance of the species to Cladocarpus integer would also seem to point in the same direction; the last-named species has hitherto likewise been regarded as a Halicornaria, but, as is further explained below, it is as a matter of fact a primitive Cladocarpus, whose phylactogonia do not always or everywhere attain development. We cannot therefore altogether disregard the possibility that Halicornaria campanulata may also under normal conditions develope more or less regularly occurring phylactogonia. But as long as this has not been shown to be the case, the species must remain in the genus Halicornaria. Ritchie (1912 p. 227) could not state the locality of origin of the species nearer than “from the neighbourhood of Iceland”, which from a bio-geographical point of view is very meagre inform- ation indeed. The localities now recorded are the more surprising, since we should @ friorz suppose The Ingolf-Expedition. V. 7. ue. 74 HYDROIDA II / that we have to deal with a form from the warmer Atlantic regions; both the finds are in fact from near the north coast of Iceland. At the same time, however, it should be noted that both are situate in water of positive temperature; at the “Ingolf St. 127 no less than 5,6°; it is thus not impossible that the occurrence of the species here is due to larval transportation from the Danmark Strait. Arctic the species certainly cannot be; even the one Aglaophenitd hitherto found in any number in arctic water layers, 7hecocarpus myriophyllum (Lanné) is not indigenous there. We must therefore regard the Avlaopheniide on the whole as southern visitors in the colder northern seas. Hf/alicornaria cam- panulata must likewise be placed in this category; its true home, however, has yet to be discovered. Nematocarpus nov. gen. Singly or doubly pinnate cojionies, the apophyses of the primary stem tubes bearing hydrocladia, which in fully developed colonies are secondarily branched. All sarcothecze immobile. The secondary hydrocladium is formed from the proximal sarcotheca branch on the primary, and stands in no relation to the gonangia. The latter are not surrounded by any protective organs. This peculiar genus is known only in a single species, originally described as a H/alicornaria by Allman (1874 p. 477). In Nutting’s diagnosis of this genus (1900 p. 126) we find “Hydrocladia not branched; hydrocladial internodes without septa”. The latter point is of minor importance even in distinction of species, but the first-mentioned character is also adopted by Stechow (1913 p. 43) “Hydrocladien einfach”. On the other hand, we may with some justification maintain that the genus Aglaophenopsis (Fewkes) is based on forms with branched hydrocladia. We must, however, here note a great differ- ence in comparison with //alicornaria ramulifera Allman; the secondary branches in Aglaophenopsis are hydrotheca-bearing phylactogonia, and stand thus in definite reiation to the gonangia; in this case, however, they have nothing to do with the gonangia, and do not develope into minor branches, as in Aglaophenopsis, but into secondary hydrocladia of the same structure and appearance as the primary. This difference is important, inasmuch as we should, as Bale already (1887) pointed out, establish a new genus on the basis of the same. The nearest related genera are alicornaria, Aglaophenopsis, and Cladocarpus, where we often, especially in the two last, find.the same structure of the gonotheca as in the known Mematocarpus species. Nematocarpus ramuliferus (Allman). 1874 Halicornaria ramulifera, A\\man, Report on the Hydroida.... Porcupine, p. 477, pl. 67, fig. 3. 1903 Halicornaria pluma, Broch, Die von dem norwegischen Fischereidampfer “Michael Sars” .... ge- sammelten Hydroiden, p. 8, Taf. IV, figs. 15— a1. Doubly pinnate colonies, with somewhat irregularly branched, polysiphonic main stem. The primary tube is segmented, and has on the middle of each internodium a strong apophyse, directed alternately to each side, and a pair of sarcothecee at the upper side of the apophyse; the sarcothecze are adcaulinally spiit. From the apophyse proceeds a hydrocladium, bearing a hydrotheca on each HYDROIDA II ~I wn internodium, surrounded by a pair of supracalycine sarcothecee on the distal part of the internodium and an unpaired median proximally; between this and the base of the hydrotheca arises a sarcotheca- bearing branch, which bends forward over the hydrotheca, and has on its convex (outer) side a row of sarcothecze. The sarcotheca-bearing branch of the basal hydrotheca developes into a secondary hydrocladium of the same appearance as the primary, but somewhat finer. Also in the exterior sarcothecal branches hydrothecze may be developed. The hydrothecze are fused throughout their basal half with the branch; the distal portion forms an angle with the basal, and widens some- what towards the aperture. The margin is furnished with 9 or rr teeth; a large median proximal (abeladial), beside this as a rule a couple of smaller ones, then two well marked, and finally there are distally (adcladially) a pair of large teeth of the same size as the proximal, and between them a couple of quite small ones. The gonothecee are attached by a short, often almost rudimentary stalk to the stem; viewed laterally, the gonotheca is asymmetrically egg-shaped or oval, with a distal lateral opening; seen from the front, they are oval, distally often broadly rounded; the aperture is round. At times there may be some approach to formation of ari “upper lip” above the mouth. Material: “Ingolf? St. 44 61°42’ N., 9°36’ W., depth 545 fathoms 4,8° = = OS Oseats IN Beta AC. aor 8 a 5,0° The new colonies brought home by the “Ingolf’? show that the Halicornaria pluma Broch (1903 p. 8) described as distinct species is really only a somewhat older stage of Nematocarpus ramu- liferus (Allman); we have now colonies showing the next stages through which they pass over to the possession of secondarily branched hydrocladia (fig. XXXVII@). Here also the species retains its peculiar nude posterior side, whereas the front appears even more furry than in young colonies. There are certain signs which seem to indicate that a primary hydrocladium may bear several secondary ones. Halicornaria plima was established chiefly on the strength of the fact that the basal sarcotheca- bearing branch of the hydrocladium has a hydrotheca, whereas the remaining sarcothecal branches lack hydrothecee. The present colonies now show that this was merely the forerunner of the second- ary hydrocladium, which gradually developes new hydrothecze with sarcotheca-bearing branches out- side the first. At the same time, however, we find a hydrotheca with its corresponding sarcothecal branch developed at the second, often also at the third hydrotheca, and it is therefore highly possible that in still larger colonies we may also here find developed secondary hydrocladia, showing that a primary hydrocladium can bear several secondary ones. The gonothecz are incompletely described both by Allman (1874 p. 477) and Broch (1903 p. 8) probably from imperfectly developed specimens. They are of very peculiar form (fig. XX XVII 4). They are attached by a stalk which is not infrequently very short, almost rudimentary. The one (adcauline) side is somewhat flattened and short, the other however, highly curved and a good deal longer, so that the plane of the aperture is almost or entirely parallel with the longitudinal axis of 1 In fig. XXXVIIa, the secondary hydrocladium shows only one complete sarcothecal branch (the basal); this is due to the fact that the two next are broken off. Ordinarily, they appear in fully normal development at every single * hydrotheca. IoO* 76 HYDROIDA II Fig. XXXVIL. Nematocarpus ramuliferus. a hasal part of a hydrocladium showing the development of the secondary hydro- cladium [/ primary, s secondary hydrocladium; the proximal, sarcothecal branch is a little abnormally developed]. “Ingolf” St. 44. 6 internodium of the primary tube of the stem of a young colony from “Ingolf’ St. 98. ¢ Hydrotheca, “Ingolf” St. 44. @ Gonotheca in side view and front view, ‘Ingolf’ St. 98. (@ >< 45, 2—d X 90). the gonotheca itself. The aperture is round or often somewhat broader, oval, and we thus find here a distinct approach to the remarkable form of gonotheca which occurs in all known forms of Ag/ao- phenopsis and Cladocarpus species, save that a distinct upper lip is less often clearly discernible. Nematocarpus ramuliferus was formerly only found in the cold area (fig. XXXVIII), but the two finds fall just in the zone where otherwise warmer atlantic, deeper-living visitors occur sporadi- 200 mM, we oi boom —-+-- ee 1000M, eeeenenne ween ei COCITT Fig. XXXVIII. Finds of Mematocarpus ramuliferus. HYDROIDA IT 77 cally in the Norwegian Sea, and lie also comparatively near the submarine ridges. It was therefore most likely that the species should be reckoned, bio-geographically, as belonging to the class of such visitors, and the two new finds appear to confirm this supposition, both being situate in the warmer atlantic region; one on the slope down towards the Atlantic Deep, west of the Faroe plateau, and the other on the east side of the threshold in Danmark Strait, where several other warm-water species also come in. The last-named locality, with a depth of 138 fathoms, is the shallowest of the finds made; the others lie deeper down in the true abyssal region. We are therefore justified in concluding that the species belongs to the warmer and deeper atlantic communities. Aglaophenopsis (Fewkes). Upright colonies with branched or unbranched main stem, the apophyses bearing unbranched hydrocladia with several hydrothecee. All the sarcothecee are immobile. The gonothece are protected by minor branches forming a basal appendix to. the hydrocladia, and with both hydrothecee and sar- cothecee; the gonothecz are situate on the stem or on the minor branches. Practically speaking, this definition coincides with Nutting’s limitation of the genus (1900 p. 118). Nutting also lays most stress upon the occurrence of the protective branchlets, but does not seem quite to have realised that the principal character for these lies in the fact that they bear hydrothecee, not, as in the case of Cladocarpus, sarcothecee only. Aglaophenopsis differs from Nemato- carpus in principle by the fact that the minor branches do not develope into secondary hydrocladia of normal appearance, but merely appear as protective appendices in fertile colonies. Aglaophenopsis-Cladocarpus form a pair of genera parallel with Zhecocarpus-Aglaophenia. As a matter of fact, we cannot determine which of the two in each case is the more primitive; having regard, however, to the development of a species such as Vematocarpus ramuliferus, which appears to be more primitive than the others in the state of its gonangia, we must probably incline to the theory that Cladocarpus and Aglaophenia are the more primitive, rather than the more highly developed. Still, we can hardly in either case regard the one genus as derived from the other; it would seem more likely that each has arisen independently. Aglaophenopsis cornuta (Verrill) Nutting. 1879 Cladocarpus cornutus, Verrill, Notice on recent additions to the marine fauna, p. 310. 1900 Avlaophenopsis cornuta, Nutting, Plumularidee, p. 120, pl. 30, figs. 6—9. Colonies doubly pinnate, with branched polysiphonic main stem, monosiphonic in its extreme portions. The primary stem tube is divided into short internodia, bearing in the middle an apophyse directed obliquely forward and sideways, and three sarcothecze, one pair nearest the upper side of the apophyse, and an unpaired one medially on the lower part of the internodium; all are split along the upper side, and project far forward, especially the paired ones. At the base of the apophyse, between it and the unpaired sarcotheca, there appears a pattern which must be interpreted as an abortive hydrotheca. The hydrocladia have on the rear side a markedly prominent keel; they are divided into short internodia, each bearing a large hydrotheca and three sarcothecee, a supracalycine pair at the 78 HYDROIDA II opening, and a median proximal sarcotheca, the opening margin of which hardly reaches up to the middle of the hydrotheca; the sarcothecee have a dentate margin, and project far forward; they are adcaulinally split. The hydrotheca is laterally compressed; seen from the side, it is egg-shaped and pointed at the lower end. The hydrotheca has abcaulinally a median keel, running out into a large, hollow, generally sharply horn-shaped tooth, the free projecting part of which may reach a length of up to 2/, that of the hydrotheca; the cavity forms a continuation of the lumen of the hydrotheca. The hydrotheca margin has at the base of the mentioned projection a median abcauline tooth, and on either side four teeth, which become broader and _ less pro- nounced nearer the hydrocladium. The internodium has four to six inner ribs at the hydrotheca wall; an inner rib also bounds the lumen of the proximal sarcotheca on its lower end. The hydrotheca Fig. XXXIX. Aglaophenopsis cornuta, lacks inner ribs or septa. Ingolf” St. 25. — a. Cauline interno- The gonothecee are set on the stem, or more often on short, dium of the primary tube, showing oe : both sarcothecce of the upper pair.— Once dichotomically divided branchlets proceeding from the basal 6. Front view of the internode, show ing the abortive hydrotheca at the base of the apophyse above the proximal small branches bear as a rule a hydrotheca on each branchlet; more sarcotheca. (> 40). internodium of the hydrocladium beside its proximal sarcotheca; the rarely the one may have two hydrothecee, the other one. The gono- theca is broad oval to pear-shaped; seen from the side it is somewhat more slender, with subterminal opening on the adcladial side and with a short upper lip, formed by the abcladial wall, which is domed forward roofwise over the opening. Material: “Ingolf” St. 15, 66°18’ N., 25°59 W., depth 330 fathoms +-0,75° — =§ 215), 62°30 INES GsAcon We. = 582 = 353° = =) 98% 105e38m Ney 26227 Wn = 1h = 5,9° Greenland: Davis Strait, — 100 — (without further details) 657530) N55 55.36) W., — 289 — In Nutting’s description of Aglaophenopsis cornuta (1900 p. 120) there is a misunderstanding as to the cauline sarcothecze, which he describes as follows: “cauline nematophores very large, one just at the base of each hydrocladium, another immediately below this, and a third, long and = spur- like opposite the base of each hydrocladium”. As regards the last sarcotheca (fig. XXXINq@) this is as a matter of fact one of a pair situate nearer the upper side of the base of the apophyse; both of them project far out from the stem, but on viewing the colony from the front (fig. XX XIX 4) the one is hidden by the basal part of the hydrocladium. The lower, proximal sarcotheca is very broad, and does uot project quite as much. The sarcotheca which Nutting mentions as just at the base of the hydrocladium, i.e. practically on the apophyse itself, must on the other hand be regarded as an abort- ive hydrotheca which has been checked in its development by the growth of the apophyse and hydro- cladium; it bears no resemblance to the remaining sarcothecee, and does not seem to be provided with any sarcostyle or nematophore. A point of great importance in this explanation is also the fact that the basal portion of large pinnate parts may be formed of internodia with hydrothecee, but witbout HYDROIDA II 79 apophyses and hydrocladia; here again we find the supracalycine sarcothece particularly well devel- oped, in the same manner as over the apophyse, and more than on the normal cladial internodia; at the same time there is not the slightest indication of any such pattern as that which Nutting has taken for a sarcotheca. The abortive hydrotheca probably forms a parallel to the apophysal “mamelon” in Nemertesta and Polynemertesia, and would seem to throw some light on its origin. There is considerable variation in the appearance of the hydrothecz (fig. XL) especially owing to the fact that the abcauline keel and its prolongation vary very greatly both in length and breadth; the outgrowth may be broad and blunt, or more slender, and running out to a point. It forms an incurvation in the wall of the hydrotheca; at its base, the hydrotheca is furnished with a sharply cut tooth, directed obliquely inward and forward, and between this and the internodium the edge shows = 2 Fig. XL. Aglaophenopsis cornuta, a Basal part of a hydrocladium with the phylactogonium and a gonotheca in side view from “Ingolf” St. 98 (x 4o). — 4 Front view of a hydrotheca from the same colony ( 60). — c¢ Side view of a hydrotheca from the same colony (% 60)/ — d Hydro- é U theca from a colony from “Ingolf’ St. 25, side view ( 60). as a rule four teeth on either side, which become broader and lower nearer the hydrocladium. The innermost tooth on either side, and at times the one next to it, can even now and again be entirely effaced, so that only two abcauline teeth can be distinguished on either side. — The proximal sarco- theca also varies considerably, diverging now more, now less widely from the hydrotheca, and having a free portion of varying length. The basal internodium of the hydrocladium has a different structure owing to the position of its proximal sarcotheca. This is shifted to the obliquely upward trending hydrocladium, — the side away from the stem — and is also somewhat smaller than'on the following internodia. The cause of this must be sought in the growth of the phylactogonium. The phylactogonium (fig. XL, a) is segmented and has only hydrothecze on two of its branches; on one of them at times two, but as a rule only one on each; they are surrounded by the usual three 80 HYDROIDA II 200 Mm. Ses Kid Pane OLO.OTIs Fig. XLI. Finds of Avlaophenopsis cornuta in the Northern Atlantic. sarcothecee, which, however, are here generally somewhat smaller than on the hydrocladia. The gono- theca has a well developed upper lip, which does not appear clearly from Nutting’s illustration and description. It is domed strongly forward, so that the aperture becomes turned down towards the base. Aglaophenopsis cornuta is a typical deep-sea species which has only in Davis Strait been observed at roo, and in Danmark Strait at 138 fathoms depth; it can thus also penetrate up into the lower part of the littoral region. The species probably belongs strictly speaking to the warm, deep northern part of the Atlantic; it moves up into Davis Strait, where it appears to be of not infrequent occurrence (fig. XLI) and has now, as we see, also been recorded from Danmark Strait. As it is not known from other localities than those mentioned and the waters off Nova Scotia, we are justified in characterising it for the present as a west atlantic species. Aglaophenopsis (?) pharetra un. sp. The colony pinnate with polysiphonic stem, monosiphonic in the extreme portions, and having the primary tube indistinctly segmented. Each of the internodia of the stem bears at two thirds of its height a well defined, fairly short apophyse, and three unpaired sarcothece, two in the median line below the apophyse, and the third in the corner between the stem and the apophyse above the origin of the latter. The alternately placed hydrocladia form almost a right angle with the stem; they are divided into long internodia, each of which bears a hydrotheca, and three sarcothecz, a supracalycine pair at the opening of the hydrotheca and an unpaired proximal about midway between the base of the hydrotheca and the proximal end of the internodium; the opening margin of the HYDROIDA II Sr proximal sarcotheca does not reach up to the base of the hydrotheca; all the sarcothece have a smooth margin and are adcaulinally split. The length of the hydrotheca is about three-fifths that of the inter- nodium. The hydrotheca is of extremely slender build, not laterally compressed, somewhat expanded towards the opening; the opening margin is quite smooth. Numerous small inner ribs are found in the internodia along the hydrotheca wall; a rib also forms the lower boundary of the proximal sarcotheca. Material: “Ingolf? St. 81 61°44’ N., 27°00’ W., depth 485 fathoms, 6,1°. Of this remarkable species we have only a single quite small colony, the height of which amounts to only about 2 cm. above the close rootlike net- work by which it was attached. The upper 6 mm. bear the hydrocladia, two fairly long on each side, and there is also, at the top of the colony on the left side, a third hydrocladium where the hydrotheca no 2 is still only indicated. On the lower part of the stem there is a secondary tube, which creeps upward along the lower 7 mm. of the primary, show- ing that the fully grown colony will exhibit a poly- siphonic stem. The primary tube differs from that of most other species in the arrangement of the sar- cothecee (fig. XLII a); paired cauline sarcothece are lacking, but each internodium has three unpaired sarcothecee; the two lower in the median line one a a g Fig. XLII. Aglaophenopsis (?) pharetra from “Ingolf’ St. $1. a. Internodium of the primary cauline tube with the apophyse. upper side of the apophyse. é. Internodium of the hydrocladium with hydrotheca in side view. c. Frontal view of hydrotheca and internodium. (> 60). above the other, and the third in the corner at the The hydrotheceze are very characteristic (fig. XLII 4, ¢, in appearance not unlike a slender quiver, whence the species has been named pharetra. The opening margin is quite smooth, without indication of teeth or irregularities. The supracalycine sar- cothecze project somewhat up beyond the hydrotheca opening. The proximal sarcotheca is separated by a quite considerable interval from the hydrotheca. As no indications of gonangia have yet been found, the systematic position of the species cannot yet be determined with certainty. It presents, however, a so considerable resemblance to A claophenopsis Verrilli Nutting that it should, for thé present at any rate, be placed near tiis; the differences consist in the somewhat shorter and broader hydrothecz of the latter species, where the opening is furnished with teeth, as also in the much shorter distance from the hydrotheca to the proximal sarcotheca. The species is therefore placed with a query in the same genus, under the name of Aglaophenopsis (?) pharetra. On the other hand, it also resembles not a little certain Cladocarpus The Ingolf-Expedition. V. 7. = II HYDROIDA II oe) NO species such as Cladocarpus tenuis Clarke and Cladocarpus flexuosus Nutting. There is therefore the possibility that the species may have to be referred to this genus, and the query affixed to the generic name must remain for the present. Only the one specimen was found, in the deep south west of Iceland. The locality suggests that we have here to deal with a warm-water form from the deep water of the Atlantic. Cladocarpus Allman Upright colonies with branched or unbranched main stem, the apophyses with unbranched hydrocladia with several hydrothecz. All the sarcothecee are immobile. The gonothecz are protected by small branches, phylactogonia, which form a basal appendix to the hydrocladia, and are furnished with sarcothecee, but lack hydrothecee. The gonothecee are set on the stem or on the phylactogonia. Cladocarpus integer (G. O. Sars). 1874 Aglaophenia integra, G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 100, pl. 2, figs II—I5. 1879 Cladocarpus Pourtalest, Verrill, Notice on recent additions to the marine fauna, p. 309. 1893 Cladocarpus Holmi, Levinsen, Meduser, Ctenophorer og Hydroider, p, 67, tab. VIII, figs. 15—18. The colonies are doubly pinnate with branched polysiphonic main stem, exhibiting only in its very outermost parts the primary segmented tube alone; this has fairly short internodia, bearing on the basal third a strong but short apophyse; the internodium is also furnished with three adcaulinally split sarcothece, an unpaired median at the bottom, and a pair at the upper side of the apophyse. The internodium of the hydrocladium has a fairly large hydrotheca and three sarcothecee, a supra- calycine pair at the opening, and a median proximal sarcotheca, which with its opening margin hardly reaches up to the basal fourth of the hydrotheca; all the sarcothecze approach the tubulous form, but are adcladially split. The hydrothecee are laterally somewhat compressed, and slightly expanded at the opening; the opening margin, in the hydrothecee as in the sarcothecze, is quite smooth. The inter- nodium exhibits one or two inner ribs at the hydrotheca wall, and two below the proximal sarcotheca. The gonothecee are fastened as a rule by a rudimentary stalk to the stem or to the phylac- togonia, which are almost invariably unbranched, and have two irregular rows of sarcothecze; the phylactogonium proceeds from the basal internodium of the hydrocladium, beside the proximal sarco- theca. The gonotheca is somewhat flattened; seen from the flat side it is broadly pear-shaped, broadly rounded distally; viewed laterally, it is a slender oval, with a distal lateral adcauline opening over which the abcauline wall domes out like an upper lip. Material: “Ingolf St. 25 63°30’ N., 54°25’ W., depth 582 fathoms, 3,3° — 27 904° 54 NG 55 tO Wo) 305) 0 ee _ - 94 64°56’ N., 36°10’ W., — 204 — Avs = - 98 65°38’ N., 26°27’ W., — 138 —_— 59° HYDROIDA II 83 Greenland: Davis Strait, depth 80 fathoms (without further details) |type specimen of Clado- carpus Flolmt| Iceland: 5 miles E. of Seydisfjord, depth 135 fathoms |labelled Cladocarpus Holmz\. Cladocarpus integer has led a somewhat unsettled existence in various genera. G. O. Sars (1874 p. 100) regarded it as an Aglaophenia, and is followed by Bonnevie (1899 p. 93) who places all northern Avlaophenide in this one genus. Jaderholm (1909 p. 109 and 110) refers to it either as Halicornaria integra or as Cladocarpus Holmi and Cladocarpus Pourtalesi, while Ritchie (1912 p. 228) classes the species under Halicornaria, A very rich material from the Trondhjem Fjord, where the species is found in great numbers, enabled me to study it further, and determine its systematic position, And it now turns out that the species must be regarded as a primitive Cladocarpus. The 4) : Fig. XLIII. Cladocarpus integer. a. Basal parts of a hydrocladium and its phylactogonium with an entire gonotheca, from the Trondhjem fjord (> 40). — 4. Hydrotheca of the : same colony ( 60), — c, Hydrotheca of a colony from “Ingolf’ St. 98 1 (X 60). gonothecee are very often fixed to the stem or more correctly, to the apophyses; Ritchie’s descrip- tions show that this may often occur on the whole for an entire colony, and that the phylactogonia may in consequence be altogether lacking, which is also exceptionally found to be the case in some of the colonies from Trondhjem Fjord. The great majority of the colonies have, however, at any rate in considerable parts of each, developed primitive but typical phylactogonia (fig. XLIII a). These pro- ceed from the basal internodium of the hydrocladium beside the proximal sarcotheca. The phylacto- gonia are practically always unbranched, and furnished with two somewhat onesidedly arranged rows of sarcothecze, set either in pairs or irregularly placed; only once or twice have I found phylactogonia which had, by dichotomic division, developed a short lateral branch of the same structure. The phylac- togonium also exhibits irregular segmentation. It has as a rule two or three gonothecze on the same side as the sarcothece. The gonotheca is of the typical Cladocarpus form, with upper lip; this is, however, shorter than in most other species, so the opening is not yet directed downwards. Ritchie’s specimen (1912 p. 228) should, it would seem, be taken as the representative of a special variety Azéchier noy, differing from the typical form in having the hydrotheca margin slightly TE 84 HYDROIDA II sinuous. The internodial ribs of this variety are also somewhat more strongly marked than in the common form, and it likewise shows a more pronounced indication of intrathecal septum. The features mentioned, that the species can at times lack phylactogonia, show that Clado- carpus Pourtalest must be considered as a synonym. The difference between this species and Clado- carpus Hlolmit is not apparent from Levinsen’s description of the latter (1893 p. 67) and an investig- ation of the type specimens shows that the species has been founded on typical colonies of Clado- carpus integer. Seep eee OO OLTTs, Fig. XLIV. The distribution of Cladocarpus integer in the northern Atlantic. In the hatched regions the literature denotes a scattered occurrence. The species is a typical warm atlantic form, which appears to have its chief occurrence in the western Atlantic, in the lower part of the littoral region and the upper part of the abyssal. In northern waters, it has long been known from the west coast of Norway, and is also found to be a not alto- gether infrequent visitor to Greenland, both in Davis Strait and up towards Danmark Strait (fig. XLIV). On one occasion, it was met with off the east coast of Iceland, at the boundary of the arctic deep region. That it has not yet been located with certainty between the British Isles and Iceland must be due to accident. Ritchie (1912 p. 228) had before him a specimen brought home by Hull trawlers, and we may doubtless presume that it would then have originated from the northern slope of the North Sea plateau or from the Faroe Islands Banks, HYDROIDA II 85 Cladocarpus formosus Allman. 1874 Cladocarpus formosus, Allman, Report on the Hydroida..... Porcupine, p. 478, pl. 68, fig. 1. 1893 Cladocarpus crenulatus, Levinsen, Meduser, Ctenophorer og Hydroider, p. 68, pl. VIII, figs. 13—14. The colonies have an unbranched or branched polysiphonic stem. The primary, foremost tube is divided into short internodia with a short apophyse directed obliquely forward and sideways, and three sarcothecze, a pair at the upper side of the apophyse, and an unpaired median on the basal part of the internodium, -all adcladially split. The internodia of the hydrocladium are short, and bear a large broad hydrotheca and three sarcothecee, a supracalycine pair at the hydrothecal aperture, and Fig. XLV. Cladocarpus formosus. a Basal part of a hydrocladium with its phylactogonium, “Ingolf” St. 29 (>< 40). é Hydrotheca of the same specimen (> 60). c Hydrotheca of the variety from “‘Ingolf’ St. 25 in side view (X 60). d Front view of a hydrotheca of the same specimen (> 60). a median proximal, which reaches with its opening margin nearly up to the middle of the hydrotheca; the sarcothec have a slightly dentate margin, and are adcaulinally split. On the basal internodium of the hydrocladium, the proximal sarcotheca is divided off by an interval from the hydrotheca. The hydrothecee are large, and nearly circular in transverse section, with an abcladial intrathecal septum; the opening margin is slightly sinuous, with more prominent teeth abcladially, and with a quite di- stinct abcladial median tooth. The gonothece are situate on the stem or on the phylactogonia, which proceed from the basal internodium of the hydrocladium, at the interval between the hydrotheca and the proximal sarcotheca, The phylactogonia have, after two dichotomic divisions, three branches, and bear on their outer side two rows of paired or irregularly placed sarcothecee. The gonothece are somewhat flattened, pear- shaped from the broad side, with transversely rounded distal part; seen from the side, with a terminal lateral opening over which one wall domes out in a markedly prominent upper lip. 86 HYDROIDA II Material: “Ingolf” St. 25 63°30 N., 54°25’ W., depth 582 fathoms 3,3° — =§'20) 05034" INF icacam! We — 68 _ 0,2° — - 34 65°07 N., 54°57°W, .— 55 = — = 403) (6422700INI 352A" TW, — 767 — 1,46° — ' = 97 Vo5t28' IN,” 27°39 W. 1 450) 55° _~ - 127 66°33''N:,. 20°os) W., — 44 _ 5,0° Greenland: Davis Strait, depth 80 fathoms (without further details) [type specimen of Clado- carpus crenulatus| 65°39’ N., 28°25’ W., depth 553 fathoms [type specimen of Cladocarpus crenulatus|, Cladocarpus formosus is described in detail by Ritchie (1909) from some colonies taken at about the same place as Allman’s type specimens. Among the features which he here notes is the fact that the opening margin of the sarcothece is “serrate”. Most of the present colonies fully agree with Ritchie’s careful description. We have, however, from the “Ingolf? St. 25, in addition to many typical colonies, also some few of slightly different structure (fig. XLV). The hydrothecz are here somewhat broader than the normal, the septum is set a little deeper down, and goes consider- ably farther in towards the adcladial side than in ordinary colonies of the species, while on the other hand the internodial sibs are less pronounced, and fewer in number. Furthermore, all the sarcothecze here have smooth opening margin. The points of difference, as compared with the typical form of Cladocarpus formosus, are thus sufficiently marked; they are however, too slight to warrant our mark- ing off a distinct species, since no other differences can be discerned. The colonies should thus merely be regarded as representatives of a special variety within the species. Ritchie (1909 p. 314) points out that Levinsen’s Cladocarpus crenulatus (1893 p. 68) must be regarded as a synonym of Cladocarpus formosus; and after having examined Levinsen’s type specimens, I must entirely concur in this view. Bonnevie (1899 p. 95) mentions Aglaophenia formosa from a station near Spitzbergen; her description however, differs not a little from Allman’s, and from those of later writers; in the first place, no mention is made of the intrathecal septum, in addi- tion to which, the description of the hydrotheca as “almost cylindrical, regularly dentated round the margin” is hardly in accordance with what we otherwise know of the species; the published drawings (1898 Taf. 2, fig. 3) also differ somewhat, so that the identity of the colony seems doubtful. An investi- gation of the type specimen, however, shows that the intrathecal septum is present, and that the spe- -ciinen only differs from the colonies here in question in the somewhat more distinct and regular den- tition of the hydrotheca margin. In addition, one of the phylactogonia is pinnately branched, as in Cladocarpus paradiseus Allman, while the others are dichotomically branched. Cladocarpus formosus is plainly one of the most common forms in the warmer tracts belonging to the upper part of the abyssal region in the North Atlantic (fig. XLVI) and penetrates thence up into the lower part of the littoral region. It is originally known from the southernmost part of the cold area, where the latter runs into the Faroe Channel, but should here be regarded as a visitor, brought in by larval transport with the Atlantic current. The species is previously known from HYDROIDA II 87 Davis Strait, from where the “Ingolf” brought back several colonies, and has now also been found in deeper water right up in the Danmark Strait. From here again, it may be transported into the waters along the north coast of Iceland, as shown by the find at the “Ingolf” St. 127, where the species occurs together with Halicornaria campanulata. 200 m. ga teas OOO Fl oscckttes ence 1ooom. waa 2 OOO NK Fig. XLVI. Finds of Cladocarpus formosus in the Northern Atlantic. Cladocarpus Diana nov. sp. The colonies are singly pinnate with polysiphonic, in the upper parts monosiphonic main stem, which is not particularly strongly pronounced. The primary tube is indistinctly segmented, with long internodia, each having on its upper third an apophyse turned almost straight out to the side, alter- nately directed to either side of the stem. The internodium further has three or four sarcotheca, a pair at the upper side of the apophyse, and one or two unpaired in the median line on the lower part of the internodium; all are adcaulinally split. The internodia of the hydrocladium have a large hydro- theca and three sarcothece, a supracalycine pair at the hydrotheca aperture, and an unpaired median proximal sarcotheca which reaches with its opening margin barely a little beyond the bottom of the hydrotheca, The supracalycine sarcothecee approach the tubulous form, but are adcladially split; the proximal is of very typical shape, being much widened out laterally towards the opening, so that the latter is seen to be as broad as, or even slightly broader than, the lower part of the hydrotheca; the free adthecal wall has disappeared; the margin is slightly dentate. The hydrothece are large, some- what compressed laterally, with expanded opening part; the margin of the aperture is armed with 9 strong teeth, an abcladial median, and between this and the internodium four on either side. There 88 HYDROIDA II is an indication of four to five faint inner ribs in the internodium at the hydrotheca; the proximal _ sarcotheca is bounded on the lower side by a strong rib. The gonothece are situated on dichotomically branched phylactogonia proceeding from the basal internodium of the hydrocladia beside its proximal sarcotheca. The phylactogonia have three branches, which bear, on the side, turned towards the stem, a row of sarcothecze, and can be indistinctly segmented. The gonotheca is somewhat flattened; seen from the broader side it is a broad oval, or egg-shaped, fastened by the pointed end to the phylactogonium. The opening is broad, subterminal, and turned downwards owing to the fact that the abcladial side curves far out beyond the opening as a broad upper lip. Fig. XLVII. Cladocarpus Diana. “Ingolf’ St. 78. — a Phylactogonium with gonotheca (>< 4o). 6 Hydrotheca in side view ( 60). — ¢ Hydrotheca in front view (> 60). Material: “Ingolf? St. 46, 61°32’ N., 11°36’ W., depth 720 fathoms 2,4° = = 978; 00:370N., 9 27°52) Wa —— 7995) pt 845 Cladocarpus Diana has much stronger hydrothecal teeth (fig. XLVII) than most other species of the genus; nearest in this respect is Cladocarpus compressus Fewkes, but the teeth there are some- what broader; in addition, the intervals between the teeth in Cladocarpus Diana are curved somewhat outwards. The most remarkable character, however, lies in the proximal sarcotheca. Seen from the side, this does not differ greatly from other previously known species, being only unusually short, so that the opening margin does not extend much beyond the bottom of the hydrotheca. But on exam- ining the sarcotheca from the ventral side (fig. XLVIIc) we find that it has its greatest breadth at the opening margin, which may even be slightly longer than the breadth of the lower and middle part of the hydrotheca, The sarcotheca has only one opening, which is correspondingly larger, the free wall turning towards the hydrotheca being entirely effaced. HYDROIDA II 89 Cladocarpus Diana exhibits also certain peculiarities in the gonosome (fig. XLVII a). The phyl- actogonium divides dichotomically a little above the base, and the outer branch, that farthest from the median line of the colony, soon divides again dichotomically into two, giving a slightly upward curving phylactogonium with three short branches. These have only a single open row of strong sarcothecze on the side turned towards the median plane of the colony; each branch has from three to five sarcothecee. The branches of the phylactogonium are richly furnished with inner ribs, and are also often irregularly segmented. The phylactogonia bear two or three gonothece of the same type as that usual in the genus, with a strongly developed upper lip domed out roofwise over the broad opening, which is turned towards the phylactogonium. The colony from the “Ingolf” St. 46 exhibits the peculiarity of having the outer branch of the seventh phylactogonium from below on the left side prolonged; at the terminal point of the normal branch arises a further lateral branch; the outer branch is further prolonged, and has, outside the above-mentioned supernumerary branch, three hydrothecee, and thus from here presents the appearance of,a Hydrocladium, which in addition to its basal hydrotheca further shows the incipient develop- ment of a secondary phylactogonium. The entire formation must be regarded as an abnormity. Cladocarpus bicuspis (G. O. Sars) Jaderholm. 1874 Aglaophenia bicuspis, G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 98, pl. 2, figs. 7—10. 1909 Cladocarpus bicuspis, Jaderholm, Northern and Arctic Invertebrates, p. 110. The colony is pinnate with polysiphonic, in the outer portions monosiphonic main stem. The primary tube is divided into short internodia, each bearing an apophyse directed obliquely forward and sideways, turned alternately to either side of the median line. The internodium is further provided with three sarcothec, a pair at the upper side of the apophyse, and an unpaired one in the median line of the internodium, close below the apophyse; all are adcaulinally split. The internodia of the hydrocladium have a very large hydrotheca and three sarcothecee, a supracalycine pair at the hydro- theca aperture and an unpaired median proximal reaching up to the lower third of the hydrotheca; all sarcothece are adcladially split, and have quite smooth margins. The hydrothece are laterally much compressed, with outward curving opening margin, and with an abcauline pair of large teeth; the margin otherwise smooth; the sinus between the teeth is almost square. The teeth are concave, the incurvation strongest at the median line. From the sinus between the teeth an inner rib runs along the abcladial side of the hydrotheca to its middle, where it terminates in a strong S-shaped intrathecal septum, dividing the hydrotheca into a larger upper portion and smaller basal part, the latter half the size of the former. The internodium is furnished at the hydrotheca wall with four or five short ribs, the proximal sarcotheca is bounded on the lower side by a an oblique septum. The gonothece are situate on the stem or on short, dichotomically three- to four-branched phylactogonia, proceeding from the basal internodium of the hydrocladium beside its proximal sarco- theca. The phylactogonia are furnished with sarcothece irregularly arranged, and not infrequently having indistinct segmentation. The gonotheca is somewhat flattened; from the broad side it is reversely r The Ingolf-Expedition. V. 7, 12 go HYDROIDA II conical, broadly rounded distally, with a broad opening towards the phylactogonium; in lateral view, the abcladial wall is seen to dome out in a large upper lip over the opening, which is consequently turned downwards towards the base. Material: “Ingolf? St. 51 64°15’ N., 14°22’ W., depth 68 fathoms 7,32° = = 98 65°38’ N., 26°27) W., = — 138) = 95,9" Of this highly peculiar species, a couple of well developed colonies have been found; it re- sembles somewhat Cladocarpus paradiseus Allman, with its two strong abcladial teeth, but these are Fig. XLVIII. Cladocarpus bicusprs from “Ingolf” St. 98. a Basal part of a hydrocladium with its phylactogonium (>< 40). 6 Side view of a hydrotheca (> 60). — ¢ Front view of a hydrotheca (> 60). more strongly developed in Cladocarpus bicuspis (fig. XI,VII]) than in the species mentioned, and their appearance is the more striking from their marked incurvation, which renders the median sinus more prominent. The strong S-shaped septum is suggestive of Cladocarpus sigma Allmann; on the other hand, the inner longitudinal abcladial keel seems to be without parallel in the genus. The phylactogonia are dichotomically branched, the ramification does not always take place once only, as in the one shown (fig. XLVII1a), but as a rule two or three times, so that we have three or four terminal branches. The gonothece shown by G. O. Sars (1874 pl. 2, fig. 8) are not yet fully grown. The full-grown gonotheca presents the same typical appearance as the remaining north- ern Cladocarpus species, with a much more strongly developed upper lip domed out over the open- ing; it is here as strongly developed as in Cladocarpus Diana. Cladocarpus bicuspis is altogether a rare species in the regions investigated (fig. XLIX) and as it does not seem to have been found at all elsewhere, its true habitat is still a matter of doubt. In the northern waters, the species belongs to the typical visitors from the warmer atlantic waters, being previously known only from between Stavanger and Trondhjem Fjord on the west coast of HYDROIDA IL gI Norway; now the “Ingolf’ has added two new localities, the one being off the south-east point of Iceland, the other in the eastern part of Danmark Strait, at a spot where several representatives of the heat-loving deep-water fauna of the Atlantic have been found. The bathymetrical position of the species is also somewhat doubtful: up to the present it has only been found in the middle and lower parts of the littoral region. OG Gi @ Oe em Se boom. acasttese - 000m, ee 2 OOO MM: Fig. XLIX. The occurrence of Cladocarpus bicuspis in the Northern Atlantic. In the hatched region the literature notes a scattered occurrence. Gen. Thecocarpus Nutting. Upright colonies with branched or unbranched main stem, the apophyses bearing unbranched hydrocladia with several hydrothecz. All sarcothecee immobile. The gonothece are set in a corbula formed by a metamorphosed hydrocladium; the blades of the corbula, or ribs, have each a hydrotheca near its point of origin. Nutting (1900 p. 106) attaches primary importance to the question whether the stem is mono- siphonic, a character which, even in distinction of species, is of subordinate weight; a species such as Thecocarpus myriophyllum (Linné) occurs in northern seas not infrequently fertile with monosiphonic stem, while other colonies have a polysiphonic basal part; but it is really only in southern waters that strong colonies of this species are found with polysiphonic stems, at any rate a couple of feet high. This feature, then, is of little or no interest from the point of view of generic distinction; on 12% 92 HYDROIDA II the other hand, it is perfectly correct to’take the furnishment of the corbula blades with hydrothecze as of primary importance, which Billard (1913 p. 85) also points out. The breadth of the single cor- bula blade however, is of minor significance in this respect, and cannot be taken as proof that the corbula here is more primitive than in Aglaophenia, where narrow-bladed corbulz have also been found. Thecocarpus myriophyllum (Linné) Nutting. 1758 Sertularia myriophyllum, Lanné, Systema nature, ed. 10, p. 810. 1900 Thecocarpus myriophyllum, Nutting, Plumularide, p. 107, pl. 24, figs. 12—13. The colonies have an unbranched or branched, polysiphonic or monosiphonic main stem. The primary tube of the stem is divided into shorter or longer internodia, each bearing about the middle a short apophyse, directed obliquely forward and sideways; at the base of this at its upper side there is a pair of sarcothecze, and on the basal part of the internodium an unpaired median sarcotheca. The short internodia of the hydrocladium have each a large hydrotheca, slightly compressed laterally, and three sarcothece, a supra-calycine pair at the hydrotheca opening and a short proximal unpaired sar- cotheca, the opening margin of which does not reach up to the middle of the hydrotheca; all sarco- thecze are adcaulinally split. The hydrotheca margin is furnished with a strong, sharply cut median abeauline tooth; between this and the hydrocladium the margin is slightly dentate or curved, more faintly near the hydrocladium than farther from it. The opening margin stands almost perpendicular to the hydrocladium. The gonothece proceed from a hydrocladium which is transformed into a narrow-bladed cor- bula having its blades (ribs) furnished with a basal hydrotheca, and in addition, on the outer side, numerous sarcothecee. Between the corbula and the stem the hydrocladium has a varying number of hydrothecee. The gonotheca is pear-shaped. Material: “Ingolf”? St. 15 66°18’ N., 25°59’ W., depth 330 fathoms + 0,75 _ = 35) G5 200 NS 555054 W., — 362 — 3,6° — - 81 61°44’ N., 27°00’ W., — 485 - Gxie “Thor 62°18" (N., 215307 W., depths 78) metres — 61°15’ N., 9°35’ W., — 872 — Iceland: 3 miles E. of Bjarnaroi, — 70 fathoms. Thecocarpus myriophyllum is undoubtedly the most frequently occurring Aglacphenid in the eastern part of the North Atlantic (fig. L). It is therefore highly peculiar that it should now have been met with for the first time by the “Ingolf”’ in Davis Strait, where no specimen had previously been found. In Iceland waters also, reliable data have hitherto been extremely rare, though Se- mundsson (1g91r p. 105) records the species from the south-west point of Iceland, albeit under the name of 7hecocarpus radicellatus. We can now add the further finds in these waters from Danmark Strait and east coast of Iceland. Vhecocarpus myriophyllum is a species belonging to the lower littoral HYDROIDA II 93 region of the warmer seas and the upper abyssal region; quite exceptionally it may penetrate deeper down, as seen from the above. In the boreal regions it is not altogether rare, and has even in a single instance been met with in the cold area. 200 Mm. SSo ceo oO UOTE te eee 1o00om, masse ate tee IORI. Fig. L. The distribution of Zhecocarpus myriophyllum in the northern Atlantic. In the hatched regions the literature notes a common, although scattered occurrence. Gen. Aglaophenia Lamouroux. Upright pinnate colonies with branched or unbranched main stem, the apophyses bearing un- branched hydrocladia with several hydrothecee. All sarcothecze immobile. Gonothecee in a corbula formed by a metamorphosed hydrocladium; the corbula blades (ribs) are furnished with sarcothece, but lack hydrothece. Aglaophenia tubulifera Hincks. 1861 Plumularia tubulifera, Hincks, A catalogue of the Zoophytes of South Devon, p. 256, pl. 7, figs. I—2. 1868 Aglaophenia tubulifera, Hincks, A history of the British Hydroid Zoophytes, p. 288, pl. 63, fig. 2. The colonies are pinnate with unbranched or branched monosiphonic main stem divided into short internodia. The internodium has close below the middle an apophyse directed obliquely forward and sideways, and three tubulose sarcothecee, a pair at the upper side of the apophyse and an unpaired 94 HYDROIDA II one in the median line near the base. The internodia of the hydrocladia have each a hydrotheca and three sarcothecee, a supracalycine pair near the hydrotheca aperture and a median proximal of greatly varying length. The proximal sarcotheca is tubulose, and has an open connection with the lumen of the hydrotheca; in the outer parts of the hydrocladium, it forms a more acute angle with the branch axis than nearer the stem; its free parts are in forma /yfzca up to 2/, the length of the hydrotheca, in forma 4rl/ardi however, as a rule longer than the hydrotheca. The hydrotheca margin has an abeauline tooth, and on either side, between this and the hydrocladium, three, or more rarely four teeth. One or two internodial ribs are seen at the wall of the hydrotheca; at times an intrathecal rib may be indicated. The gonothecee are situate on a hydrocladium which has broad lateral blades converging to a corbula; the basal pair of blades is as a rule free, and hangs out and downwards; there is a hydro- theca between the corbula and the stem. The gonothecze are pear-shaped. Material: “Thor, 35°57’ N;, 5°35: W., ‘depth 740 metres. The synonymy of the species has been dealt with in detail on a previous occasion (Broch 1912 p. 8) and notice has also been taken of the variations. Geographically, Aglaophenia tubulifera is a southern species, only quite exceptionally passing beyond the limit of the boreal waters round the British Isles; it belongs more especially to the middle and lower parts of the littoral region. Family series Sertulariina nov. Family Sertulariide. The hydrothece are bilateral in structure and furnished with closing apparatus formed of from one to four plates. The colonies form sympodia or monopodia with terminal growth point. The polyps have a more or less pronounced abcauline and basal blind sack with a low, non-digestive endodermal epithelium; they are therefore bilaterally symmetrical. Few families have been the subject of so much dispute as the Ser¢ulariide, both as regards limitation and also in respect of division into genera. The best foundation is that given by Levin- sen in his latest work (1913) where he comes to the same result as Stechow (1913). The latter writer here separates off the Sytheciide as a distinct family comprising those forms which lack the lid; but while Levinsen also discards this group and refers it to the family Lefoéide, Stechow considers the .Syzthectide as an independent family, most nearly related to the Sertularide sens. strict — a view in which we may fully concur, owing to the homogeneous organisation of the polyps. This principle for division is not very fully dealt with by Levinsen, and in particular the special organisation of the abcauline blind sack and its endodermal peculiarities seem altogether to have escaped his attention. This is suggested, as already mentioned, by his reference to a blind sack in Lictorella pinnata (G. O. Sars) which from a purely anatomical point of view is hardly tenable. Com- HYDROIDA II 95 mon to Syxthecude and Sertularide@ is also the exterior ectoderm lamella, which forms an inner wall covering to the hydrothecze; a parallel formation is, it would seem, found only in Agdaopheniide, where it is less pronounced. From the anatomical agreement of the polyps in the two families, and the fundamental differences in the structure of the polyps as compared with the remaining thecaphores, I have found it most correct to take the two families together in a distinct family series Sertulariina. With regard to division into genera, however, I can on the whole agree with Levinsen, as will be seen from the following. Nevertheless it should be noted that the generic subdivision is still far from satisfactory. A considerable amount of anatomical investigation will be required before we can obtain a thoroughly adequate foundation here, and the present material, unfortunately, is not suit- able for such studies. In face of the above diagnosis, it may be objected that a genus such as Diphasza lacks the blind sack, at any rate, appears to do so. This point is not without importance, and has its own parti- cular interest in consideration of the genus from a phylogenetic point of view. On closer examination of the group of species which Levinsen classes together in the genus Sertularella, we find that there are here, as a matter of fact, two distinct anatomical groups, which ought really to be separated as independent genera. The more restricted genus Ser/iwlarella will then comprise the species in which a closing apparatus consisting of 3 or 4 flaps is found together with polyps having fully developed abcauline blind sack; this class includes the great majority of species. On the other hand we have a group of species with the same sort of closing apparatus, but with polyps in which the blind sack is rudimentary or entirely lacking as far as can be seen from external observation. For this group, then, a special genus should be established. The group in question exhibits a close affinity to Thyroscyphus, which again forms a link with Campanulinide, and from this genus we must pre- sume that the entire family has its origin. A species such as Sertularclla tamarisca (Linné) belongs to this group of the Sertwlarel/a, and represents the transition stage to genera with rudimentary blind sack, Diphasia and Dynamema. From the second group, again, are derived the remaining genera with their marked lines of development in the closing apparatus. Taking into consideration both the organ- isation of the hydranth, and the structure and development of the closing apparatus, we come to fixed lines of development within the family, which are best illustrated by the following scheme: ' Odontotheca Hydrallmania Thigaria Sertularia Diphasta Dynamena A bietinaria a. Polyps with rudimentary blind sack, — Serteularella — &. Polyps with blind sack. Thyroscyphus g6 HYDROIDA II Gen. Sertularella Gray. Upright colonies with sympodial growth. The opening of the hydrotheca is furnished with three or four marginal teeth, between which are attached as many triangular opercular plates closing in a pyramid over the aperture. The definition here agrees with that given by Levinsen (1913 p. 30). The genus seems, how- ever, to form a somewhat heterogeneous collection of species which should, probably, from the struct- ure of the polyp, be divided into two groups or genera. Of these groups, Sevfewlarella sens str. will then comprise species with abcauline blind sack, while in the other group, we have species where this is rudimentary or indiscernible on external observation. The latter group leads, as above menti- oned, to Diphasia and Dynamena, while the former gives the point of origin for the remaining genera of Sertularude. The most primitive group is that of the species without visible blind sack. Sertularella tamarisca (Linné) Levinsen. 1758 Sertularia tamarisca, Linne, Systema naturee, ed. 10, p. 808. 1893 Sertularella tamarisca, Levinsen, Meduser, Ctenophorer og Hydroider, p. 58. Upright, somewhat irregularly branched, as a rule pinnate colonies, without distinct main stem. The hydrothecze, which have a tripartite lid and tridentate opening margin, are set in two rows along the branches, a pair of hydrothecze oppositely placed on each internodium. The hydrothece are very large, almost cylindrical, with the distal half free and highly diverging from the branch. The male gonothecee are reversed conical, compressed distally with a small tooth on either side and a short cylindrical neck centrally placed. The females are of the same shape, but have three distal broad blades, each furnished with a longitudinal indented median ridge; the three blades close in to a pyramid and form a large external marsupium, in which the larvee are developed. Material: “Ingolf’ St. 11, 64°34’ N., 31°12’ W., depth 1300 fathoms, 1,6° — - 87, 65°02,3' N., 23°56,27W., — 110 — — - 95, 65°14’ N., 30°390' W., — 752 — Pepe = = 98, 65°38 N.. 26°27)1Wi, ==) 6138 en ecige — = 1445 62-40 Ni 7ol2saWe — 276 a 165 “Thor” 3°30 IN-y 20-14 We, — 80 metres Iceland: 6 miles W. of Isafjord, depth 55 fathoms 5 — KE. of Seydisfjord, — 135, — Gae2meeN ews W7eG. Wie, = 58 = The Faroe Islands: 16 miles S. by E. of south point of Nols6, depth. 80 fathoms. Sertularella tamarisca presents, as a matter of fact, a somewhat alien impression among the remaining Sertularella species, and has led an unsettled existence, now in this genus, now in Diphasia or Dynamena. The paired arrangement of the hydrothecee and the remarkable female gonothece of HYDROIDA II 97 the species, with the marsupial chamber resembling that of Diphasia fallax (Johnston) and Diphasia rosacea (Iinné) have led to its being frequently referred to this genus. The state of the material did not permit of a quite certain investigation of the polyps, but as far as it was possible to judge it has a quite rudimentary blind sack, which brings the species nearer to Difhasia. On the other hand, the closing apparatus is altogether of the same type as Sertudaredla, thus removing the species again from Dzphasia. The most natural thing would doubtless be to consider Sertularella tamarisca as the type of a distinct genus, which in a certain degree forms a link between the true Ser¢zlaria species and Diphasia. This would demand, however, in the first place a closer study of the structural 200 m. Soe 5555000 re tea 000M. svonien semana lowe 210100) (T1, Fig. LI. The distribution of Sertularella tamarisca in the Northern Atlantic. In the hatched regions the literature notes a scattered occurrence without giving particular data. conditions of the species, and as my material is not suited to the purposes of such investigation, I have for the present refrained from establishing the new genus here. It is not altogether easy to determine with certainty the biogeographical character of the species. Sertularella tamarisca is not a form of frequent occurrence, and is never met with in large numbers at a time; on the contrary, it is as a rule taken in single specimens, so that the species appears to be somewhat of a rarity. Further study seems to show that it is a boreal species capable of penetrating slightly into the arctic area and even more into warmer waters. Towards the north, it comes up into the White Sea, and towards the south, as we know, it penetrates into the Mediter- ranean. In the waters investigated (fig. LI) the species has not infrequently been found in the eastern part of the boreal region, while it has only once been met with in Davis Strait; it never penetrates into the cold area, despite the fact that its wide bathymetrical range would seem to suggest a con- The Ingolf-Expedition. V. 7. 13 98 HYDROIDA II siderable elasticity in respect of physical conditions. The chief occurrence of the species falls in the lower part of the littoral region and the upper part of the abyssal. Sertularella tricuspidata (Alder) Hincks. 1856 Sertularia tricuspidata, Alder, A notice of some new genera and species, p. 356, pl. 13, figs. 1—2. 1868 Sertularella tricuspidata, Hincks, A History of the British Hydroid Zoophytes, p. 239, pl. 47, fig. 1. Upright colonies with pinnate or quite irregularly bushy ramification; in the pinnate colonies, the branches are alternating or subalternating, not infrequently they may themselves be dichotomi- cally or pinnately branched; the branches are often bent or twisted. The monosiphonic stem and branches are segmented; each internodium has a hydrotheca. The hydrothecz are situate on the distal part of the internodium, and are cylindrical or slightly barrel-shaped, with their narrowest part immediately below the aperture; they have three teeth of equal size on the aperture margin, the one median adcauline; in the sinuses between the teeth, the three triangular plates of the closing apparatus are attached. The adcauline wall of the hydrotheca has a free distal part between half and two-thirds the length of the hydrotheca. The polyp has a well-developed abcauline blind sack. The gonothecee are attached under the base of the hydrothecz. They are oval to pear-shaped, with a short and narrow, reversedly conical, distally central neck, and with deep transverse furrows. Material: “Ingolf’, beach of Jan Mayen. — St 3 63°35’ N. 10°24’ W., depth 272 fathoms 0,5 aot pS SA 05217 9 5427), Wo ee MS ems = — - 54 63°08 N., 15°40' W., —— 691 -- 3,9° — =) 87.1105°02\2! IN3723-50)25 Wy 8 LO — _ _ = OS OS 714" Ni a sOr 30m We, — 752 — Zit “Thor” 65°52’ N., 23°58’ W., — 62 metres ~ 65°29,5' N., 24°63’ W., — 40 — — 64°02' N., 22°33’ W., = 34 = — 63°30' N., 20°r4' W., ~ 80 -— Greenland: mouth of Nerak (depth not stated) Hunde-Eiland ( — - — ) Egedesminde, depth 30—40 fathoms Store Hellefiskebanke, — 24 _ Sukkertoppen, on Ao/tenza (without further details) Frederikshaab ( — — — ) Iceland: Bakkefjord, depth 25—32 fathoms Lonafjord, = 40 == Malarif (depth not stated) Reydarfjord, — 60-80 — [labelled \Sertularella polyzonias| 63°21’ N. 17°15! \W. sae 58 a HYDROIDA II 99 Iceland: Vestman6, depth 25 fathoms 10 miles W. of Akranes (depth not stated) [labelled Ser/udarella polyzonias Bredebugt, depth 7—12 fathoms 65°00’ N., 24°38’ W., —=' 22 — Onundarfjord — 10 — Adalvik (depth not stated). The Faroe Islands: 7 miles N. by E. of Myggenees point, depth 57 fathoms -6 — N. by W. of Store Kalsé, — 60 — Deep hole at north point of Nolso, — I100-'— 5 miles 5.S.E. of Bispen, — 5 — Sertularella tricuspidata is a circumpolar arctic species which is extremely numerous in arctic waters. From there is penetrates far down into the boreal area (fig. LII) where it is one of the most common species, especially round the Faroe Islands, Iceland, and off West Greenland. Along the east coast of Greenland, however, it is distinctly rare. Its infrequent occurrence off the north coast of Iceland on the other hand, should probably rather be apparent, as the result of insufficient in- vestigations. Along the west coast of Norway, Sertularella tricuspidata goes southward as far as Bergen; according to the literature, it is also met with near the British Isles, but we have no certain data from here, so it would seem that this must be about the limit of its distribution. Bathymetri- cally, it belongs to the littoral region, exceptionally, however, it may, as shown by the find at the “In- golf” St. 95, penetrate quite far down into the abyssal. tae ae ee eee tooom,. Some 2000mM,. Fig. LIIl. The distribution of Sertularella tricuspidata in the Northern Atlantic. In the hatched regions the literature notes a scattered occurrence. 100 HYDROIDA II Sertularella amphorifera Allman. 1877 Sertularella amphorifera, Allman, Hydroida..... of the Gulf Stream, p. 22, pl. 15, figs. 8—ro. 1912 Sertularella amphorina, Bedot, Matériaux pour servir a l’histoire des Hydroides, 4” période, p. 352. Upright slender colonies with monosiphonic hydrocaulus. Stem and main branches slightly prominent. The basal part of the stem is straight, irregularly segmented, without hydrothece and branches; higher up, it becomes regularly segmented, like the branches, with a hydrotheca on the distal part of each internodium. The branches arise in irregular alternation, and may themselves again ramify; like the hydrotheca-bearing part of the main stem, they are bent zigzag fashion. The hydrothece are large, cylindrical, slightly curved, with three equal sized, markedly prominent teeth, and in the sinuses between them three large triangular lid plates. The hydrotheca is attached to the branch by a narrow base. The polyp has a distinctly prominent abcauline = blind sack. "| i) e The gonothecz proceed from below the base of the hydrothece. They are a slender oval to pear-shaped, with a distally central narrow ; f Fig. LIL. Sertudarella amphorifera from “Ingolf’ St. 54. a. Part of a branch (X 20). b. Hydrotheca of the stem with the basis of a branch ( 4o). neck, and distinct transverse furrows; the neck passes evenly over into the gonotheca. Material: “Ingolf St. 7, 63°13’ N’, 15°41’ W.; depth 600 fathoms, 4,5° — - 54, 63°08' N., 15°40’ W.; — 691 - 3,9° Nutting (1904 p. 88) who had only some fragments of Allman’s type specimen to work on, states that Sertularella amphorifera as possibly four hydrothecal teeth, and he gives some drawings where four such teeth are markedly in evidence, as if his specimen had been intact, and not, as he himself expressly notes in the text, defective. Billard (1906 p. 183) on the other hand, reports the species as distinctly tridentate, and this is also plainly to be seen from my specimens (fig. LHI). Be- tween two branches on the stem, the number of hydrothecz varies from two to five. Sertularella amphorifera is evidently very closely related to Sertularella tricuspidata, extreme variants of which may present a strong resemblance to the former. On the whole however, Ser/zla- rella amphorifera seems to be of considerably more open growth, while its finer structure and long, slender internodia, together with the strongly projecting hydrothece, give it a typically different appearance from Sertzzlarella tricuspidata, as is apparent at the first glance. The finding of Sertularella amphorifera so far to the north is highly interesting. It was pre- viously known only from the sea off Florida at Double Headed Shot Key, 471 fathoms, and from the west coast of Africa, where it was taken at 882 metres’ depth. The species thus belongs to the warmer parts of the Atlantic abyssal region, and moves up, in the warm, deep water layers, to the deep off the south-east coast of Iceland, HYDROIDA II IOI Sertularella polyzonias (Linné) Gray. 1758 Sertularia polyzontas, Linné, Systema nature, ed. 10, p. 813. 1848 Sertularella polyzontas var. a, Gray, List of the specimens of british animals, p. 68. Upright colonies with irregularly branched monosiphonic hydrocaulus, no distinct main stem. The branches are divided by oblique nodes into internodia, each bearing a hydrotheca, turning alter- nately to either side. The hydrothecee are smooth or slightly wrinkled transversely, barrel-shaped, with a somewhat expanded opening part; the opening margin has four low and broad teeth, between which are attached the four triangular lid plates.) The adcauline wall has a longer or shorter free part, according as the hydrotheca diverges more or less sharply from the branch. The polyp has a well- developed abcauline blind sack. The gonothecz proceed from close under the base of the hydrothece. They are egg-shaped, deeply furrowed transversely throughout their entire length, and have four markedly prominent strong teeth about the distally central opening. Forma /yfrca: fine and low colonies. Forma gigantea (Mereschkowsky): large robust colonies. Material: Forma /ypica: Iceland: Bredebugt, depth 35 fathoms (transitional to forma gzgantea). 63°20’ N., 20°14’ W., depth 80 metres. The Faroe Islands: 6 miles N. by W. of Store Kals6, depth 60 fathoms. Forma gigantea: “Ingolf” St. 127 66°33’ N., 20°05’ W., depth 44 fathoms Greenland: Akudlek — 30—60 — [labelled Sertetlarella polyzonias| Jakobshavn (depth not stated) | — — -— | Egedesminde — - — Store Hellefiskebanke (without further details) = — depth 32 fathoms Godthaab (without further details) [labelled Sertelarella polyzontas| Davis Strait, 67°34’ N., 55°29 W. [ — _ — Sukkertoppen on oltenza (depth not stated) Kara Sea, “Dijmphna” [labelled Sertularella polyzonias\. Sertularella polyzonias is divided by many writers into two species, the gigantic arctic form being regarded as a distinct species, Sertularella gigantea Mereschkowsky. Kirchenpauer (1884 p. 34) has already drawn attention to the existence of intermediate forms between the two, which cannot show a single qualitative difference, the latter for instance, being distinguished merely by the fact that all dimensions are harmoniously increased. The very fact that this form belongs to the arctic and antarctic water layers, while the other is quite cosmopolitan, warns us to be careful about regarding them as distinct species. Geographical studies on the variations of hydroids have shown (cf. Broch 1go9, 102 HYDROIDA II 1913, 1914) that the dimensions may here quite commonly become coarser within the same species as the temperature decreases. In Sertularella polyzonias forma gigantea, this common law has been fol- lowed to an extreme, while the transition forms are comparatively few. That they exist, however, is plainly evident from the present material, where in particular certain colonies from Jakobshavn, Greenland, and all those from Bredebugt take up a doubtful intermediate position. Forma giganica (fig. LIV) is atypical arctic (and antarctic) character form, only exceptionally capable of penetrating into the boreal region. It is extremely common in West Greenland waters, and is also known from East Greenland; occasionally also from the north coast of Iceland. Forma /yfvca, on the other stersrcorersesveres 200 M, ww ow = = ow 0100) Mm; OSes -— tooom. Seperene OCOM Fig. LIV. Finds of Sertularella polyzonias forma typica @ and forma gigantea + in the Northern Atlantic. In the hatched regions the literature notes a common occurrence of the forma fyfzca. hand, is cosmopolitan, and occurs also, albeit less frequently, in arctic waters. In the boreal area, it is particularly numerous in the eastern parts. Both forms belong to the middle parts of the littoral region, and rarely move down into the deep sea region. Sertularella Gayi (Lamouroux) Hincks. 1821 Sertlaria Gay, Lamouroux, Exposition méthodique des genre.,. p. 12, pl. 66, figs. 8—o. 1868 Sertularella Gayi, Hincks, A History of the British Hydroid Zoophytes, p. 237, pl. 46, fig. 2. Upright, irregular doubly pinnate colonies with distinctly prominent polysiphonic main stem and main branches. The outer branches are almost regularly pinnately branched often with their minor branches secondarily ramified. The outer branches are divided by indistinct oblique joints into short internodia, having on their distal half a large hydrotheca; the hydrothece are directed alternately to HYDROIDA II 103 either side in the broad plane of the colony. The hydrotheca has a free adcauline distal wall part, half as long as the hydrotheca or somewhat less, about 1'/, times the opening diameter. The hydro- theca has its greatest breadth at the middle, and narrows down both towards the base and towards the opening, which is set perpendicular to the axis of the hydrotheca. The free portion of the adcau- line wall is as a rule furnished with somewhat faintly marked transverse furrows. The opening margin has four low teeth and four triangular lid plates in the sinuses between them. The gonothece proceed from the branches close under the base of the hydrothecee. ‘They are oval, more or less furrowed transversely in the distal half, and have distally a narrow central opening with two diametrically opposite short broad teeth. 200 m. ene Sens YOULL Saws mes avian tooom. eee, 2000M. Fig. LV. The distribution of Sertudaredia Gayi in the Northern Atlantic. ' In the hatched regions a common although scattered occurrence is stated in the literature without precise data. Material: “Ingolf’ St. 1 62°30 N., 8°21’ W., depth 132 fathoms 7,2 = = BS opaey ING) sey We — 316 oe 5,9 — ee S5euOs ea IN ez See wi, — 170 — — — - 94 64°56’ N., 36°10) W., — 204 — 4,1° — - 98 65°38 N., 26°27’ W., — 138 - 59° Som 64°06' N., 23°14’ W., — 98 metres [labelled Svrtelarella polyzonias Iceland: Ingolfsh6fdi 9!/, miles in N. by E."/,E., depth 53 fathoms. The Faroe Islands: 60°23’ N., 8°55’ W., — 225 104 HYDROIDA II Sertularella Gayt is an atlantic warm-water species, which in the northern waters (fig. LV) exhibits an easterly distribution. It belongs to the deeper littoral and upper abyssal regions, where it is parti- cularly frequent. In the south-eastern part of the boreal area it is quite common, and moves hence down into the cold area in the Faroe Channel; it is not altogether rare off the south coast of Iceland, where it seems now and again to have been confused with Sertularella polyzonias. The “Ingolf” has a single specimen from St. 94, so that the species can also occur in deep water off the south-east coast of Greenland, outside the mouth of Danmark Strait, where the deeper parts are still covered with warmer atlantic water layers. Sertularella tenella (Alder) Hincks. 1856 Sertularia tenella, Alder, A notice of some new genera and species, p. 357, pl. 13, figs. 3—6. 1868 Sertilarella tenella, Hincks, A History of the British Hydroid Zoophytes, p. 242, pl. 47, fig. 2: Upright, unbranched or slightly branched openly constructed colonies with monosiphonic hydro- caulus. Stem and branches are divided by joints into not very long internodia, each having on its distal part a very slightly imbedded hydrotheca; proximally, the internodium is furnished with a pair of rings. The stem and branches are bent to an angle at the nodes, which gives them a mark- edly zigzag course. The hydrothecee are large, about as long as the internodia, elongated oval, with somewhat more cylindrical opening part; they are distinctly furrowed transversely between the base and the cylindrical opening part. The aperture is set perpendicular to the longitudinal axis of the hydrotheca. The opening margin has four low teeth, and in the sinuses between them four tri- angular lid plates. The polyp has a well-developed abcauline blind sack. The gonothecee proceed from stem and branches close under the base of the hydrothecz. They are oval to more pear-shaped, transversely furrowed throughout their entire length, and furnished with a distal central short, almost cylindrical neck. Material: “Ingolf” St. 94 64°56’ N., 36°19’ W., depth 204 fathoms 4,1° — =95 .65°14" IN. 30°30) Wa '— 752 _ Ae” As a synonym to this species I have previously (1909 p. 126). noted Sertaularella pellucida. J a- derholm has, however, (1909 p. 99, Taf. XI, figs. 8—11) given a closer study of this species, from which it appears that it does not belong here, its entire structure being different, and the colonies more resembling those of Sertelarella fusiformts. Kramp (1914 p. 1037) characterises Sertularella tenella as a cosmopolitan species. This must, however, as will be seen from the chart (fig. LVI) be taken with some little reserve. The species is alto- gether more sporadic in its occurrence within the northern waters, save probably for the tracts immediately round the British Isles, where it appears to be more common. Otherwise, it follows im the northern areas the same laws as do the warmer atlantic species, and is somewhat rare in the strictly boreal water layers. v. Lorenz, (1886) mentions the species from Jan Mayen, but this determination would seem, from the remaining data, to be somewhat uncertain. HYDROIDA II 105 SSsooocnoVOOGs -—_ aes 1000M. nee oa O.OOLTte Fig. LVI. Finds of Sertularedia tenella in the Northern Atlantic; In the hatched regions the data are not altogether precise. (o doubtful locality). Sertularella fusiformis Hincks. 1861 Sertularia fusiformis, Hincks, A Catalogue of the Zoophytes of South Devon, p. 253, pl. 6, figs. 7—8. 1868 Sertularella fusiformis, Hincks, A History of the British Hydroid Zoophytes, p. 243, pl. 47, fig. 4. 1907 Sertularella pellucida, Jaderholm, Uber einige nordische Hydroiden. 1909 Sertularella pellucida, Jiderholm, Northern and Arctic Invertebrates, p. 99, Taf. 11, figs. 8—11. Open and finely built, zigzag and slightly branched upright colonies with monosiphonic stem. The stem and branches are divided into short internodia which form an angle one with another, and are more or less distinctly ringed, more rarely quite smooth. From the same internodium may often proceed two or three branches, or simple internodia. The large, somewhat spindle-shaped hydrothece are situate on the outer half of the internodium, and are very slightly embedded; the opening part is again as a rule somewhat expanded; the aperture is set perpendicularly to the axis, and has four not very prominent teeth, between which are attached four triangular lid plates. The gonothecze are attached to the branches or stolons. They are elongated oval to egg- shaped, in the latter case with the broader part somewhat below the middle. The gonotheca has a distal central aperture with four strong teeth. Material: “Ingolf St. 3 63°35’ N., 10°24’ W., depth 272 fathoms, 0,5°. The Ingolf-Expedition. V. 7. 14 106 HYDROIDA II Sertularella fusiformis assumes a highly characteristic appearance from the peculiarity that it has often on stem or branches two or three short branchlets proceeding simultaneously from the same point, these short branchlets consisting of a single internodium, or more rarely a couple, with large hydrothecee almost terminally placed. An excellent picture of this is given by Jaderholm (1909 Taf. 11, fig. 9). His specimens undoubtedly belong to Sertelarella fusiformts, and are only remarkable in having the internodia entirely smooth; here, however, all transition stages occur, so that we are not warranted in setting aside the specimens on such ground as types of a distinct species. Sertularella fusiformis is probably a warm atlantic species, but its occurrence is little known. In the waters investigated, it is previously known from the Hebrides, and from the Clyde Sea area; to these, Jaderholm adds a single find from Spitzbergen, and the species has now also been taken by the “Ingolf” about midway between the Faroe Islands and Iceland. Sertularella rugosa (Linné) Hincks. 1758 Sertularia rugosa, Lanné, Systema nature, Ed. 10, p. 809. 1868 Serteularella rugosa, Hincks, A History of the British Hydroid Zoophytes, p. 241, pl. 47, fig. 2. Upright, irregularly branched small colonies without pronounced main stem; the latter is mono- siphonic. The colony is divided by oblique nodes into short internodia, each bearing a hydrotheca directed alternately to either side, and situate on the upper half of the internodium. The hydrothecz are broad oval or barrel-shaped, with deep transverse furrows, which are particularly marked on the abcauline side, where a very deep furrow is always found immediately beneath the aperture. The opening forms an angle with the hydrotheca axis, and is turned away from the branch; it is furnished with four low, often somewhat indistinct teeth, between which four triangular lid plates are attached. The polyp has a large abcauline blind sack. The gonothecze proceed from the internodia close under the hydrothece. They are egg-shaped or more oval, with deep transverse furrows, and have distally a central broad opening, surrounded by four short strong teeth. Material: Jan Mayen, depth 15 fathoms (East Greenland expedition). Iceland: Grindavik (depth not stated) 10 miles W. of Akranes, on alge Stykkisholm, depth 30 fathoms Bredebugt (without further details) igh Ue mecraroriece The Faroe Islands: Solmunde, on algze of Sertularella rugosa Thorshavn, on alge, depth 3—4 fathoms. from Herlé near Bergen (X 40). Vestmanhayn, — 35-4 = The available illustrations of Servtularella rugosa are very little characteristic, and this applies especially to Nutting’s (1904 pl. 17, figs. I—s5) which present an entirely misleading impression, in- asmuch as they suggest that the hydrothecée are distinctly ringed. A new drawing is therefore given here (fig. IL.VII) showing the deep transverse furrows; particularly characteristic is the deep abcauline furrow beneath the aperture. HYDROIDA II 107 Sertularella rugosa must be characterised as a boreal species, having its bathymetrical distri- bution in the upper half of the littoral region, though it does not often penetrate up into the tidal zone. Kirchenpauer (1884) records it as found at Greenland, but there are no subsequent finds recorded from there. In the areas investigated (fig. LVIII) it has, it will be seen, an easterly distri- bution from Iceland to up in the Barents Sea, but its occurrence in the purely arctic area is quite sporadic, while on the west coast of Norway, for instance, it is a characteristic species in the laminaria zone. New finds are those from the Faroe Islands, where the species might be expected to be found from its occurrence off the coasts of Iceland, the British Isles, and Norway. secu ee ee 600m. tree 1000 M. Someta oo slams 21 OO OTT = Fig. LVII. Distribution of Sertalarella rugosa in the Northern Atlantic. In the hatched regions a common occurrence is noted. Diphasia Agassiz. Upright colonies, the hydrothecee having a horizontal or, slightly obliquely situated aperture without distinct teeth, but as a rule with an adcauline sinus, in which the large single opercular plate is attached. The polyps have, as far as can be seen from external observation, no abcauline blind sack. This definition differs in one important feature from that given by Levinsen (1913 p. 309), the organisation of the polyps being taken into consideration. We thus obtain a stronger and more natural limitation, and the genus then practically coincides with the group Zudiphasia Broch. It has long been a doubtful question whether the two groups Zuwdiphasia and Abietinaria should be assigned generic rank or not, attention having previously been paid only to the form of the hydrotheca as the decisive point, and distinction thus made between species having more cylindrical hydrothece or hy- 14* HYDROIDA II 108 drothecee expanding distally (Zwdphasza) from those in which the hydrothece are bottle-shaped (4 éve- tinaria). There are, however, transition forms, and the great variation in the hydrothecz in most spe- cies renders a limit such as that so drawn extremely vague. We now find, however, that the structure of the polyp is different in the two groups, the blind sack being only in the latter found in full development. This is an organisational feature of so con- siderable importance as not only to warrant, but even to demand, a generic distinction between the two groups, which also on the whole present interesting points of difference in the gonangia. In Diphasia, we find that the female gonothecee are as a rule furnished with spinous or leaf-shaped out- growths, which very often fold in together, forming a distal chamber for the brood, a marsupium. This is a biological phenomenon, and from a phylogenetic point of view of less importance; on the other hand, it is interesting to note that it here appears to occur as a constant characteristic in a whole series of related species. It is also worth noting that this feature is likewise found in Sertuda- rella tamarisca (Linné) a species which appears to form a link between Sertlarella and Diphasia. Diphasia fallax (Johnston) Al. Agassiz. 1847 Sertularta fallax, Johnston, A History of the British Zoophytes, p. 73, pl. 11, figs. 2, 5, 6. 1865 Diphasia fallax, Al. Agassiz, Illustrated Catalogue, p. 142. Upright pinnate colonies with more or less pronounced monosiphonic main stem, and as a rule with convex foreside. Stem and branches are divided into internodia, each bearing a pair of oppos- itely placed hydrothecze. The branches proceed alternately from the stem, and are themselves often sparsely branched, frequently with tendrillike terminal parts. Between two successive branches on the same side of the stem there are two to four hydrothecee, the one of them being at the corner of the branch. The hydrothece are deeply embedded, with a free distal part of the adcauline wall, in length equal to the opening diameter, or slightly less. The aperture is round, the margin with ad- cauline sinus, in which the large opercular plate is attached. The greatest diameter of the hydrotheca is at the opening. The gonothecze are situate on the upper side of the branch or on the fore side of the colony. The males are pear-shaped, with four distal short broad spines, and a short conical to cylindrical cen- tral neck. In the females, the four spines have developed into four broad triangular blades, which close in together over a distal brood-chamber in which the larval development takes place. Material: “Ingolf’ St. 3, 63°35’ N., 10°24’ W., depth 272 fathoms 05°. Variety. — = 5a) 64ers IN 14e22) WN — 68 — 7 Boe = - =P O75) 105102,3) Ni 28050;20 Ve, — 110 — = = 1299 3,0 (047245 INS 35 sds V5 0 a0 aa LO or — - 94, 64°56° N., 36°19’ W., — 204 a Alli — =F 195, OSci4a SNE we 2OncO meme, — 752 — 2\ie — - 96, 65°24" N., 29°00’ W., — 735 — 25 = — - 98, 65°38° N., 26°27' W., — 138 - 59° HYDROIDA II 109 “Thor” 66°19’ N., 23°27’ W., depth 115—120 metres. Variety. = OSA! ING, BRriey VW 62 -— 63°30’ N., 20°14’ W.. — 80 -- Greenland: Davis Strait, — 100 fathoms (without further details) Iceland: 5 miles E. of Seydisfjord, — 185 — Ingolfsh6fdi 9!/, miles in N. by E.1/2E. (depth not stated) Vestman6, depth 50 fathoms Skagi, - — 4o metres 6 miles W. of Iceland (without further details) [labelled Diphasia rosacea} QOnundarfjord, depth 10 fathoms {[ — — — | 65°39’ N., 28°25’ W., depth 553 fathoms. Between Iceland and The Faroe Islands: depth 270 fathoms (without further details). The Faroe Islands: 8—10 miles N. of The Faroe Islands ( —- a — ) 7 miles N. by E. of Myggenzs point, depth 57 fathoms 6 — N..by W. of Store Kalso, — 60 _— Deep hole at north point of Nols6, — 100 — Bor6nees 13 miles in N.75°W. — 30 — 16 miles E. by S. of south point of Nolso — _ 80 _ It may be a question whether Diphasia fallax cannot exceptionally be confused with Diphasia Wandeli Levinsen, if the latter species, as Se@mundsson opines, can occur with only two rows of hydrothecze on the branches. There are also in the present material colonies of Diphasia fallax dit- fering in appearance, so that there is some ground for further considering the point. Semundsson (1911 p. 97) mentions having found colonies of Diphasia Wandelt with only two rows of hydrothecze on the branches, and with female gonothecze, which, however, from his drawings, agree entirely with Diphasia fallax. According to a footnote in Semundsson’s work (1911 p. 98) Levinsen should, after seeing the colonies, have expressed as his opinion that they must rather be regarded as aberrant colonies of Diphasia fallax than as representatives of Diphasia Wandelt. Now Semundsson points out, in the same place, that a colony of Diphasia Wandeli from the Norwegian Sea, which he has had occasion to study, had on the basal parts of eight of its branches only two rows of hydrothecze, while the outer parts of these branches, and all the remaining ones throughout their length, had three rows of hydrothece. This reminds one not a little of the aberrant Z/eyarza, which is further described in “Fauna artica” (Broch 1909 p. 177). As the colony described by Se- mundsson is sterile, it cannot be determined with certainty. It is probably a Diphasia Wandeli, but it might also be imagined that it could be a mutant of Diphasia fallax, though this is less likely to be the case. Typical female colonies of Diphasia Wandeli with gonothecee have not yet been found; as to the males, we know that they differ from Diphasia fallax in having eight instead of four distal spines on the gonothecz, these eight spines being arranged in pairs. It is therefore impossible to say with certainty which species Semundsson had before him, as long as typical and fertile female colonies of Diphasia Wandeli have not yet been found. Saemundsson’s colonies form, moreover, only the extreme link in a continuous variation series, of which the central one is Diphasia Jallax. 110 HYDROIDA II The “Ingolf’ brought back from several of its stations colonies of the same type described by Semundsson as Diphasia Wandeli. They are stiffly built, with a distinctly marked, often some- what darker and plainly segmented main stem. Each internodium has a pair of hydrothece and a branch, directed alternately to either side, so that in these colonies, we have constantly two hydrothecce between two successive branches on the same side of the stem; of these two hydrothecee, the one (the lower) is situate in the corner by the branch. In the most extreme specimens of this variant group, we find single undivided branches. This variety is represented by a particularly pure type in specim- ens from the “Ingolf’ St. 3 and St. 93. In these colonies, there is no pronounced fore or rear side as generally seen in Diphasia fallax. This must doubtless be taken in connection with the fact that the 200017 ee ty ae 600m. ate eee OOO: Ato mente OOO ES Fig. LIX. The distribution of Diphasia fallax in the Northern Atlantic. 5 In the hatched regions a common occurrence in reported (+ the variety spoken of in the text). most marked representatives of the variety are attached to a firm underlayer, stones or mollusc shells, and not, as is mostly the case with this species, to stems of other hydroids; they thus stand more perpendicularly, and consequently develope more symmetrically, whereas the ordinary colonies, being fixed in a more horizontal position, find it better to develope more onesidedly, with an upturned “front”. Among the numerous transition forms, it will here suffice to mention some specimens from “Thor” (65°52’ N., 23°58’ W.). They are very closely allied to the group of variants described as a distinct variety, but exhibit at the same time several of the characteristic features of the main species. The stem is not quite so marked as compared with the branches, albeit its darker brown colour helps to bring it out; its segmentation is less prominent, and the branches proceed more openly and some- what irregularly, with three, or more often four hydrothecee between two branches on the same side HYDROIDA II TIT of the stem, the one hydrotheca in the branch corner. Finally, the branches and the colonies are curved, so as to present a distinctly convex foreside; the branches themselves also, are not infrequently again ramified. The colonies are thus typical transition forms, and as such occur in all shades of difference between the typical main form and the extreme, regularly pinnate variants, we cannot separate the latter as a distinct species. Kramp (1914 p. 1053) has very appropriately characterised Diphasia fallax as “an atlantic boreal species only sporadically found in arctic regions”. Its occurrence in the north Atlantic (fig. LIX) shows, however, that it is still not quite universal in the boreal waters; it appears, strangely enough, to be very rare off the west coast of Greenland, where we should otherwise have expected to find it of common occurrence in the mixed company of southern and northern forms found in Davis Strait. Bathymetrically, its chief occurrence falls in the middle and lower part of the littoral region, and the upper part of the abyssal; at times it may penetrate far down into the latter, as is shown by the list of finds from the “Ingolf”. It is consequently the more remarkable that Diphasia fallax should seem to disappear at a somewhat greater distance from the coasts. A glance at the chart shows that the species has very rarely indeed been taken far from islands or continent, and this cannot be accidental, since the investigations both of the “Ingolf’ and later expeditions have been carried out to a very great extent in the open sea within the areas in question. The explanation of this must be left to future studies. Diphasia Wandeli Levinsen. 1893 Diphasia Wandels, Levinsen, Meduser, Ctenophorer og Hydroider, p. 55, pl. 8, figs. 1—5. Upright pinnate colonies with pronounced dark monosiphonic main stem. The stem is divided by transverse nodes into short internodia, each bearing a pair of hydrothece placed oppositely, and a branch under the base of the one, turning alternately to either side of the stem. The branches are likewise divided up into short internodia, each having three hydrothecz in a wreath; there are thus three rows of hydrothecze on each branch. The hydrothece are deeply embedded; the adcauline wall has a free distal part about one-fifth to one-fourth the length of the hydrotheca, between half and once the opening diameter. The opening is set almost perpendicular to the branch axis; the margin has a slight adcauline sinus, in which the large opercular plate is attached. "The gonothecz arise on the branches close under the base of the hydrothece. The males are reversely conical, with eight short paired spines on the distal part; the narrow distally central aperture has a rudimentary neck, or none at all. Material: Greenland: Davis Strait 65°22’ N., 54°02’ W., depth 66 fathoms [Levinsen’s type specimen]. Diphasia Wandeli appears to be a very rare species; typical three-rowed colonies have, besides the spot mentioned, only been found once, near Papey, East Iceland. All the other specimens recorded by Semundsson (1902 p. 67 and rior p. 97) belong properly to the above described variety of Dz phasia fallax. ‘The two finds belong to the middle part of the littoral region. 112 HYDROIDA II Diphasia rosacea (Linné) L. Agassiz. 1758 Sertularia rosacea, Linné, Systema nature, Ed. 10, p. 807. 1862 Diphasia rosacea, l,. Agassiz, Contributions to the natural history of the United States, vol. 4, p. 355. Upright colonies without distinct main stem. The colonies are irregularly pinnate or bushily branched, segmented, and with a pair of oppositely placed hydrothecae on each internodium. The hydrothecz are slender, almost evenly tubular, with slightly divergent distal part. The free distal portion of the adcauline wall is about half the length of the hydrotheca, between 1'/, times and twice the opening diameter, rarely somewhat shorter, down to about the same length as the opening dia- In the hatched region a common occurrence is recorded. meter. The opening margin has a slight adcauline sinus, in which the large opercular plate is attached. The gonothece arise close under the base of the hydrothece. The males are pear-shaped, with normally eight longitudinal ribs, each terminating in a distal short blunt point; the gonotheca has a central short cylindrical neck. The females are also pear-shaped, with eight long ribs, of which six terminate in as many broad blades closing together over a distal brood-chamber; the two last, diametrically opposite ribs end in forward pointing horn-like outgrowths of varying length. Material: “Thor” 63°30' N., 20°14’ W., depth 80 metres. Iceland: Stykkisholm, 30 fathoms. Szemundsson (1902 p. 66) also mentions specimens of this species from Mnundarfjord, Ice- land, but a reinvestigation of his specimens shows that they must be referred to Dzphasia fallax. HYDROIDA II I13 Diphasia rosacea should doubtless be regarded as a southern species having a very wide distribution in the southern part of the boreal area (fig. LX). It has been found at several places near Iceland, and is also recorded from the Faroe Islands. Round the British Isles and in the North Sea it is very common, and very frequent between Bergen and Stat on the west coast of Norway. Having also been found in north Norway (Tananger), it will probably likewise prove to be fairly common along the Norwegian coast in the deeper part of the laminaria belt, which is its true home. Diphasia attenuata Hincks. 1866 Sertularia attenuata, Hincks, On new British Hydroida, p. 298. 1868 Diphasia attenuata, Hincks, A History of the British Hydroid Zoophytes, p. 247, pl. 49, fig. 1. Upright, often brown-coloured, pinnate colonies with slightly pronounced monosiphonic stem, the lower part often without hydrothecz or branches, and divided into internodia of irregular length; the upper part of the stem has alternating branches, which are in rare cases themselves secondarily branched to a slight degree, and may now and again terminate in tendril-like outgrowths. The branches and the upper part of the stem are indistinctly segmented; each internodium bears a pair of oppositely placed or slightly subalternating hydrothecee. Between two successive branches on the same side of the stem, there are as a rule three, more rarely four hydrothece, the lowest in the branch corner. The hydrothecze are large, tubular, the free distal part of the adcauline wall amounts to about half the length of the hydrotheca, and is somewhat more than the diameter of the opening. The hydro- theca is bent to an angle, so that its free part forms an angle of about 60° with the branch axis. The hydrotheca opening is nearly perpendicular to the branch axis; its margin has an adcauline sinus, in which the large opercular plate is fastened. The gonothecze are situate on the upper side of the branches, and proceed from close under the base of the hydrothece. The male gonothecze are oval to pear-shaped, with six faint longitudinal ribs terminating distally in as many blunt points; the aperture is centrally placed on a broad distal cone. The female gonothecz are oblong pear-shaped, and have likewise six faint longitudinal ribs, each with one or two markedly prominent spines on the distal part; the gonothece lack distal brood-chamber. ' Material: “Ingolf” St. 96, 65°24’ N., 29°00’ W., depth 735 fathoms, 1,2 EN aeOoh VO5 48, ANG 20°87 W., == 138° == 5,9° _ = 115, 70°50’ N., 8°29’ W., — 86 — Oy — - 127, 66°33’ N.. 20°05 W, — 44 = 5,6° Diphasia attenuata belongs to the littoral region of the warm Atlantic, and penetrates at times even far down into the abyssal region; the species has previously been quite frequently observed in British waters. The finds at the threshold of Danmark Strait are therefore not surprising, but that from Jan Mayen is remarkable, and must doubtless be accounted for as due to larval transportation, possibly from the waters about Danmark Strait in the same way as the occurrence at the “Ingolf” St. 127 at the north side of Iceland. The Ingolf-Expedition. V. 7. 15 114 HYDROIDA II Diphasia alata Hincks. 1855 Sertularia alata, Hincks, Notes on British Zoophytes, p. 127, pl. 2. 1868 Diphasia alata, Hincks, A History of the British Hydroid Zoophytes, p. 258, pl. 48, fig. 2. Upright pinnate colonies with a not very marked, brown, monosiphonic stem, exceptionally polysiphonic in its basal part; the stem and branches are indistinctly segmented. The hydrothecze are arranged in opposite or subalternate pairs; they may also, in exceptional cases, be alternately set. On the branches, the hydrothecee exhibit a tendency towards unilateral arrangement on the front of the colony. The branches arise alternately from the stem; between two successive branches on the same side of the stem there are three hydrothece, the lowest at the branch corner. The hydrothecze are large, bent to an angle, with a free distal portion of the adcauline wall between one-third and one-half the length of the hydrotheca, about equal to the opening diameter. The abcauline wall has at the middle, near the bend, a prominent transverse inner rib; the angle between the branch axis and that of the distal part of the hydrotheca is greater than 60°. The plane of the hydrotheca aper- ture is almost perpendicular to the branch axis; the margin has a deep adcauline sinus, in which the large opercular plate is attached. The gonothece are small, almost pear-shaped, distally quadrilateral in section, with a short and blunt distal point in each corner, and a small round distally central opening, but no neck. The female gonothecze develop no brood-chamber; they are as a rule slightly asymmetrical, whereas the males are symmetrical in structure. Material: ie} “Thor” 35°57’ N., 5°35’ W., depth 740 metres. Diphasia alata belongs to the warmer tracts of the eastern part of the Atlantic, and seems there to be mainly restricted to the lower part of the littoral region and the upper portion of the abyssal. It is a rare visitor in the northern waters, where it has been observed off the west coast of Scotland, at the Hebrides, Shetland, and the west coast of Norway from Jzren to a little north of Bergen. It has not, however, been recorded from the Faroe Islands, Iceland or Greenland. Gen. Dynamena (Lamourouy). Upright colonies with imbedded, bilaterally built hydrothecee. The hydrotheca aperture has two large lateral teeth, between which there is a large abcauline sinus and a smaller adcauline one; the latter is often divided into two by a slightly prominent median tooth. In each main sinus a mem- brane is fixed, so that the closing apparatus consists of two membranes, the abcauline with a free distal part. The polyp has no pronounced blind sack. This definition of the genus Dynamena we also find indicated by Kiihn (1913 p. 252). Levin- sen is not disposed to consider the development of a pronounced blind sack as of auy systematic importance (1913 p. 286), which view must doubtless be accounted for by his having apparently con- fused this feature in the organisation with casual S-shaped hydranth contractions. Kiihn regards the HYDROIDA II 115 disappearance of the blind sack as a secondary phenomenon, and keeps mainly to the character of the gonangia. In this, however, it is impossible to concur, as these organisational features are entirely independent one of another, and the lines of development in gonangia and polyps can clearly not be taken as of equal significance. There is, as I have often here pointed out, no reason to reduce the importance of polyp development in systematics; phylogenetically, it is the most valuable clue. And in this case, it suggests that lid formation may partly indicate converging lines, as will be seen from the diagram given under the heading of Sertularud@e. It is therefore likewise impossible to follow Levinsen in grouping Dynamena and Sertularia together in one genus exclusively from the uni- formity of their closing apparatus. Dynamena pumila (Linné) Lamouroux. 1758 Sertularia pumila, Linné, Systema nature, Ed. ro, p. 807. 1812 Dynamena pumila, Lamouroux, Extrait dune meémoaire sur la classification des Polypes, p. 184. Upright colonies with irregular, as a rule pinnate ramification, exceptionally with an indication of monosiphonic main stem. The branches are secondarily ramified in irregular pinnate formation. The colony is divided into short internodia, each bearing a pair of hydrothecze oppositely placed. The hydrotheca is deeply embedded; its adcauline wall has a free distal portion about the same length as the opening diameter, between one-fourth and one-third the length of the hydrotheca. The opening margin has two prominent lateral teeth, and in the middle of the adcauline lesser sinus is a slightly developed broad median tooth. The adcauline closing membrane has no free part; the abcauline is large, with a free distal part. The diaphragm almost radially symmetrical. The gonothecee proceed from below the base of the hydrothecze on the one side of the branches. They are pear-shaped, with a very short neck, and a round, symmetrically situate distal opening with operculum. Material: Greenland: Egedesminde Sukkertoppen Julianehaab, on Fzc2s. Kangerdluarsuanguak. , Iceland: Reykjavik, on Ascophyllum, and Fucus, and down to 4 tathoms depth. Grindavik, Bredebugt Grafarvogr Isafjord. The Faroe Islands: Strém6. Thorshayn. I have in a former work (Broch igo p. 29) pointed out that Nutting’s drawing of the gonotheca (1904 p. 27, fig. 80) is altogether misleading, presenting the impression that the acrocyst, as it projects from the gonotheca, must perforate the operculum. This is, however, not the case; the operculum opens at one side, and the acrocyst is then thrust through the opening thus made. Dynamena pumila belongs to the tidal zone, and is most frequently found on fucoids and the shallower living Laminaria; the species evinces a high degree of elasticity with regard to salinity, 15 I1I6 HYDROIDA II and thus belongs to the hydroids found farthest up in the fjords, where the salinity is greatly reduced by the inflow of river water. The species has also a wide southerly distribution, and is very common even in the Mediterranean. It is a character form in the boreal areas (fig. L.XI) where it occurs in quantities along the coasts. On the other hand, its occurrence in strictly arctic waters is very rare and sporadic. From Greenland it has been recorded at several places along the west coast, and will probably prove more frequent here than the data at present to hand would seem to show. teseseresseeeee 200 M, SO SO WOO GA - a 000m. oe mere mwenemservss 000/71. Fig. LXI. The distribution of Dynamena pumila in the Northern Atlantic. Gen. Abietinaria (Kirchenpauer). Upright colonies with hydrothecze having their opening horizontally or slightly obliquely set; the opening margin lacks distinct teeth, but has often an adcauline sinus in which the large single opercular plate is fixed. The polyp has a well developed abcauline blind sack. On comparing this definition with that given by Levinsen for the sub-genus A dzetimaria (1913 p. 310) we at once find that there is a fundamental difference, the diagnosis here given being based chiefly on the organisation of the polyp. This gives us a clear mark of distinction as against Diphasta, and necessitates the separation of the groups as two different genera. There can be no doubt that Dzphasia, as defined by Levinsen, formed a diphyletic group, and that two separate lines of development lead from the Ser¢zlarelia to the two groups. The relation in point of opercular formation must here doubtless be taken as a secondary phenomenon of convergence, in comparison with the organisation of the polyp. HYDROIDA II 117 Abietinaria abietina (Linné) Kirchenpauer. 1758 Sertularia abietina, Lanné, Systema nature, Ed. ro, p. 808. 1884 Absetinaria abietina, Kirchenpauer, Nordische Gattungen und Arten von Sertulariden, p. 29, 35. Coarsely built, pinnate colonies, the branches often secondarily branched pinnately in the same plane. The stem is zigzag, with paired subalternating hydrothecee in two rows, there are as a rule three, more rarely four hydrothecze on the stem between two successive branches on the same side, the lowest in the branch angle. The hydrothecee of the branches are set subalternately in pairs, and in two opposite rows. The hydrothecee are large, swollen at the lower end, narrowing upwards and terminating ina short slightly outward curving neck; the aperture lies obliquely or more rarely perpendi- cular to the branch axis; the margin has no adcauline sinus; the opercular plate is attached adcaulinally. The free distal part of the adcauline wall is more than half the length of the hydrotheca, and about twice that of the opening diameter. The interval between two successive hydrothecze on the same side is from half to once the length of the hydrotheca, rarely a little less. The diaphragm is of dis- tinctly bilateral structure, with a narrow egg-shaped cleft, the longitudinal axis of which lies in the broad plane of the branch. The gonothecze proceed from close under the basis of the hydrothecz, and are as a rule set on the upper side of the branch. They are oval, with a short, almost rudimentary stalk, and have a short, broad cylindrical neck. Material: “Thor” 65°52’ N., 23°58’ W., depth 62 metres OD SOON uN 21a 07 NVA ON = fol iy ING, AAG Wie) = ES — = (fo! IN, 2B Whey = afl == (ogia0) INg Bora WN SO =O ROA Ncw e300 Nie ie OS5 | ea Greenland: Store Hellefiskebanke, off Holstensborg, depth 18—20 fathoms. , Iceland: Bakkefjord (depth not stated) Seydisfjord, depth 6 fathoms Off Seydisfjord (depth not stated) Reydarfjord, depth 50 fathoms Ingolishéfdi 9!/, miles in N. by E.!/, E. (depth not stated) Vestman6o, depth 25 fathoms Reykjavik (depth not stated) Hvalfjord, depth 24 fathoms Bredebugt, 64°45,8' N., 23°55,2’ W., depth 30 fathoms 6 miles W. of Iceland, 65°00’ N., 24°38’ W., depth 22 fathoms Patreksfjord, depth 7—25 fathoms Axarfjord, — Ue} 0 == 118 HYDROIDA II The Faroe Islands: 8—10 miles N. of the Faroe Islands (without further details) 6 miles N. by W. of Store Kalso, depth 60 fathoms 7 — N.by E.of Myggenes point — 57 — Boronees 13/, miles in N.75° W. == 310) — Deep hole at north point of Nols6 — _ 100 — 13 miles W. by S. of Munken — 150 — I have in earlier works (1908, 1909) united this species with the next, the more finely built form Adbzetinaria filicula (Ellis et Solander), having overlooked the specific character which lies in the In the hatched regions a comimon occurrence is reported. peculiar diaphragm of Adzetinaria abietina, as pointed out by Levinsen (1893 p. 56). Generally speak- ing, the robuster stucture of the colonies will obviate any doubt when dealing with the last-named species, but this is not always the case. Occasionally, Adzetemaria abietina may assume a finer struct- ure (cf. Broch 1g08) and it was from observation of such doubtful colonies that I was led to combine the two species under a common name. In such dwarf colonies, however, identity may easily be deter- mined by examination of the diaphragm, which in Adcetinaria abretina is typically bilateral, whereas in Adbsetinaria filicula the development is almost entirely radially symmetrical. Abietinaria abietina is a circumpolar boreal species, capable of penetrating far into the arctic area, albeit its occurrence there is more sporadic. It can also move far to the south, and is found in the Mediterranean and at Madeira. It belongs really to the littoral region, but may exceptionally HYDROIDA II 119 penetrate down into the abyssal. In northern waters (fig. LXII) it is extremely frequent along the coast of Norway, round the British Isles, at the Faroe Islands and along the east, south and west coasts of Iceland but very rare on the north coast of the same. Along the east coast of Greenland it does not appear to have been found, but it is met with again from several parts of West Green- land. It is remarkable that it should not be represented in the large amount of material collected by the “Ingoif? expedition, but the explanation must presumably be that the species does not often live far from the coasts. Abietinaria filicula (Ellis et Solander) Kirchenpauer. 1786 Sertularia filicula, Ellis and Solander, The natural history of many curious and uncommon Zoo- pPliytess py 57) PlaG) ties: c, C- 1884 A bzetinaria filicula, Kirchenpauer, Nordische Gattungen und Arten von Sertulariden, p. 20. Finely built pinnate coloniés, the branches often secondarily ramified pinnately in the same plane as the main colony. Stem zigzag, with paired subalternating hydrothecze in two opposite rows. There are as a rule three, more rarely four hydrothecee between two successive branches on the same side of the stem, the lowest in the branch angle. The hydrothecee of the branches also are arranged subalternately in two rows. The hydrothecee have a swollen basal part, narrowing upwards, and with a slightly expanded opening margin; the opening plane is almost perpendicular to the branch axis. The opening margin lacks adcauline sinus, and has a large adcaulinally fastened opercular plate. The free distal part of the adcauline wall about half as long as the hydrotheca, and twice the opening diameter. The distance between two successive hydrothecz on the same side is about equal to the length of the hydrotheca. The diaphragm is almost radially symmetrical, with circular aperture. The gonothecze arise close under the base of the hydrothecee, and are as a rule set on the upper side of the branches. They are oval, with rudimentary stalk, and have a broad, short cylin- arical neck. Material: “Thor” 65°52’ N., 23°58 W., depth 6z metres ' = 64°02" Ni 22°33) W., — 34 — Greenland, on ascidiz (without further details). Iceland: Bakkefjord, depth 25—32 fathoms Seydisfjord, — 6—38 _ Reydarfjord, — 50 — Faskrudsfjord, — 20—s50 — Breidalsvik, — 14 — Djupivogr, _ 8 — Vestman6, — I10—I5 ~~ Faxebugt, — 25 — Stykkisholm — 30 _ Skalanes, = 7-8 — 120 HYDROIDA II Iceland: 6 miles W. of Iceland, 65°32’ N., 24°38’ W., depth 25 fathoms Patreksfjord, depth 15—5so metres Dyrafjord, (depth not stated) Adalvik, ( — - — ) The Faroe Islands: 61°07’ N., 9°30’ W., depth 410 fathoms 6 miles N. by W. of Store Kals6, depth 60 fathoms. Abtetinaria filicula is a boreal species, rarely penetrating into arctic waters, nor does it enter the warmer seas; its distribution is circumpolar. Within the area investigated (fig. LXIIJ) it is frequent srseteseeeeee, 200 M, 5 Sao UO 3 tooom. co asceamssensy =e, 2000 M7. Fig. LXIII. The distribution of Adzetinaria filicula in‘the Northern Atlantic. In the hatched regions the literature notes a common occurrence. off the west coast of Norway, and in the northern British waters; at the Faroe Islands it seems to be rare, while on the other hand it is one of the commonest species in Iceland waters, albeit lacking here along the north coast. About Greenland, Advetinaria filicula is very rare, and has only been recorded with certainty once from the west coast, near Godthaab. It belongs to the littoral region, but can quite exceptionally also move down into the abyssal, as for instance west of the Faroe Islands. Abietinaria (?) fusca (Johnston) Levinsen. 1847 Sertularia fusca, Johnston, A history of the British Zoophytes, p. 70, fig. 11. 1874 Thwaria salicornia, Allmann, Report on the Hydroida..... Porcupine, p. 473, pl. 65, fig. 3. 1878 Selaginopsis fusca, Mereschkowsky, New Hydroida from Ochotsk, Kamtschatka..... p. 436. 1913 Abietinaria fusca, Levinsen, Systematic Studies on the Sertulariidze, p. 310. HYDROIDA II 121 Stiffly built, pinnate, dark-brown colonies with undivided branches. The stem, which is mono- siphonic, is divided up into irregular internodia, and has two single longitudinal rows of hydrothecze and two rows of alternating branches; there are three hydrothecze between two successive branches on same side of the stem, the lowest in the branch corner. The branches have two rows of very closely packed hydrothece, the hydrothece in the single longitudinal rows have their oral parts alternately turned to either side, making a distinct approach to quadriserial arrangement, and the branches thus be- come almost quadrilateral in section. The hydrothece are small, entirely embedded, without any free distal part of the adcauline wall; the opening margin forms an adcauline sinus, in which the large opercular plate is attached. The hydrotheca opening is comparatively very large. 200 mM. Soo coe VOCE a ee ee .fo0om, eee a 2000M Fig. LXIV. The occurrence of Adzetimaria (?) fusca in the Northern Atlantic. (In British waters the data are somewhat vague, but note a rather common occurrence). The gonothecze are set on the upper side of the branches. They are pear-shaped, with short stalks. Material : “Ingolf”’ St. 55 63°33’ N., 15°02’ W.; depth 316 fathoms, 5,9° The Faroe Islands: 7 miles N. by EK. of Myggenzs point, depth 57 fathoms 6 — N. by W. of Store Kalsé, — 60 — Deep hole at north point of Nols6, — 100 — 16 miles E. by S. of south point of Nolso, — 80 — It is uncertain whether this species can be allowed to retain its place in the genus A dzetinarta. The Ingolf-Expedition. Y. 7. 16 122 HYDROIDA II Unfortunately, the state of the material did not permit investigation of the structure of the polyp, as to whether a blind sack has been developed or not; a query is therefore here appended to the generic name. The geographical data for Adzetinaria (?) fusca (fig. XIV) present a somewhat scattered im- pression of an atlantic species not penetrating far into the boreal waters. On the other hand, its marked local restriction is highly surprising; the entire area of distribution of the species, or very nearly so, is shown in the chart. Outside the areas marked, A dzetinaria (?) fusca has hitherto been recorded from the east coast of England and from Bohuslan (Sweden), as also, strangely enough, in a single instance from the Kola Peninsula (Jaderholm 1gog p. 95). Once also — “Ingolf” St. 55 — the species has been met with in the upper part of the abyssal region; otherwise, it has only been taken in the lower part of the littoral. Gen. Sertularia (Linné). Upright colonies with embedded, bilateral hydrothece, the opening with two large lateral teeth, between which is a large abcauline and a smaller adcauline sinus; the latter may be divided into two by a slightly prominent low median tooth. In each of the two main sinuses there is fastened a clos- ing membrane, so that the closing apparatus consists of a smaller adcauline membrane without free part, and a larger abcauline membrane with free distal part. The polyp has a well developed abcauline blind sack. The organisation of the polyp warrants the distinction here made between Ser/ularvia and Dynamena, The genus Sertularia, as here laid down, forms a well-defined whole; the separation of the different Ser/laria species, however, is an extremely difficult matter, and it is important first of all to take a survey of the various characters and their significance, in order to form an opinion as to the value of the species described from northern waters. In Jaderholm’s arrangement (1909 p. 25) we find under Zhayaria the following Sertwlaria species: Sertularia Fabric’ evinsen, Sertularia robusta Clark, Sertularia plumosa Clark, Sertularia vegae Thompson, Sertularia argentea T,inné, Sertularia cupressina Linneé, Sertularia inflata Schydlowsky, Sertularia Tolli (Jaderholm), Ser- tularia Thompsont Schydlowsky, Sertularia tenera G. O. Sars, Sertularia arctica Allman, and Sertu- laria Birule Schydlowsky; to this must be added the polyserial Sertalaria mirabilis Verrill. There is no doubt that the number of species must, on further investigation, be very considerably reduced. An examination of the variations which may occur within a single large colony will suffice to convince an unbiassed investigator that quite a number of the specific characters employed must be ranked among the more or less accidental variations, while other characters again properly belong to the category of developmental stages. It has not proved possible to procure indubitable specimens of all the 13 species mentioned, but I am inclined to ascribe this in part to their lack of solidity. I have already in a previous work (1909 p. 171) pointed out that of the above-named species, Sertularia arctica and Sertularia Thompsoni are undoubtedly synonymous with Serfelaria tenera. Ja- derholm’s drawings (1909 pl. 9, figs. 7—9) clearly show that Sertularia vege is synonymous with Sertulavia robusta, to which species Serfularta plumosa should also probably be referred. We have HYDROIDA II 123 thus brought down the number of species to 8 or 9, which figure, as will be seen from the following, must be yet further reduced. Before passing on to special treatment of the different species, however, certain remarks as to the nature of the variations will not be out of place. The form-of the colony in all young Sertwlaria specimens is pinnate, and with the except- ion of a very few species such as for instance Sertwlaria mirabilis, it appears to be a general rule that the stem sooner or later assumes a spiral coil, while at the same time the broad plane of the branches changes from the perpendicular to the horizontal, perpendicular to the axis of the stem. The cause of this spiral coiling it is difficult to determine, but the feature itself cannot be accepted as a good specific character (cf. Broch 1912 p. 13). More importance should be attached to the winding of the coil, whether right or left; the only northern species which is dextrorse is the Sertularia Fabrici. A peculiarity in all spirally coiled species is the fact that their branches are more or less markedly dichotomically ramified; as long as the colony still preserves its pinnate shape, this second- ary ramification is less pronounced, but in spirally coiled forms it is more so. The stem may be more or less prominent in one and the same species, now darker, now lighter in hue, as a rule slightly zigzag, more rarely quite straight, though this cannot be taken as a specific character. The distance between the branches proceeding from the stem likewise varies within one and the same species, and this feature has considerable influence on the habitus of the colony generally. The stem is in all species segmented; in those investigated, the internodia had as a rule one, more rarely two, and in quite exceptional cases three branches; where only one branch is present, it proceeds from the basal part of the internodium. It is not altogether impossible that the frequency of branches from the internodia may prove of some value as a specific character. The hydrothece are subject to considerable variation within one and the same species. The divergent free distal part may diverge more or less from the branch, and it is somewhat different in the pinnate and spiral parts of the colony. In the pinnate portions, the symmetrical plane of the hy- drotheca always coincides with the broad plane of the branch; in the spirally coiled part, on the other hand, we find that the hydrothecz in most of the species tend more or less towards unilateral arrange- ment on the upward side of the branch. The aperture, however, varies very little indeed, and N ut- ting’s statement (1904 p. 70) as to great variation in the character of the aperture in Sertularia te- nera,can only be ascribed to insufficient care in the investigation. Owing to this tendency to unilateral arrangement, we normally find that the hydrothecz on these branches are seen in oblique projection. This has led numerous investigators to regard certain species, such as in particular Sertwlaria argentea, as furnished with asymmetrically developed lateral teeth, whereas careful investigation shows that this is not the case. — The proportion between length of the hydrotheca and the free projecting part seems to furnish a useful specific character. The gonothece are, as already pointed out (1909 p. 172) extremely variable in Sertudarta species, and their developmental stages have more than once been used as specific characters. It is simply astonishing to see how far from critical the investigations have often been with regard to this. The grown gonothecz vary greatly in one and the same species. In species where they have no spines, they may be round in section, or angular, with a varying number of angles; this is also noted by Jaderholm (190g p. 94) but he has. not noticed that one colony may have both round and angular 16* 124 HYDROIDA II gonothecee at the same time. This character should therefore be used with caution. In species where the gonothecz are furnished with spines, the development of the spines themselves often varies greatly in gonothecz which are fully developed and bear acrocysts; their number also is subject to accidental variation in a striking degree. All this calls for discretion in using the gonothece as_ specific characters. The variational phenomena here mentioned show, that careful and critical judgement is necess- ary in defining Seréedarza species, at the same time indicating that many of the species already estab- lished have little justification for their position as such. The present material does not include all northern species, and cannot serve as a basis for thorough revision; it will nevertheless contribute to the elucidation of certain synonyms. Sertularia cupressina Linné. 1758 Sertularia cupressina, Linné, Systema nature, Ed. 10, p. 808. 1758 Sertularia argentea, Linné, Systema nature, Ed. 10, p. 809. Upright colonies, the young ones, and the basal parts of the larger ones, to a greater or lesser extent pitmate, with alternating or partly opposite branches. The older colonies have, for a shorter or greater distal part, sinistrorse spirally coiled stem, so that the branches stand in a spiral. The stem is as a rule distinctly prominent, monosiphonic, with a branch arising basally from the internodium; more rarely, the latter may have two, or quite exceptionally three branches. The branches themselves are second- arily more or less ramified dichotomically, their broad plane is in the pinnate parts perpendicular, in the spiral horizontal. Between two successive branches on the same side of the stem or in the same spiral there are two to four, as a rule three hydrothecz, the lowest at the branch angle. The branches are divided up into irregular internodia with a varying number of hydrothecz on each; the hydrothecz are on the lower branches oposite, or subalternately placed, and have a common plane of symmetry with the branch; on the upper branches they are more or less turned upward towards the upper side of the branch; i.e. with a tendency to unilateral arrangement. The depth to which they are embedded in the branch varies somewhat; the basal have a smaller, the distal a larger free distal part. The adcauline wall has a free part from one-fourth to one-half the length of the hydrotheca; from one- third to a little more than the diameter of the aperture. The hydrotheca has its greatest breadth nearly at the middle, and narrows sharply towards the aperture, less markedly towards the base. The opening has two strong lateral teeth of equal size. The abcauline opercular plate has a large free distal part. The gonothecz proceed from the branches close under the base of the hydrothec, and on the upper branches they are always on the upper side. They are pear-shaped to slender oval, and oval in transverse section, distally provided with one or two lateral teeth in a highly variable stage of development; the teeth may also be entirely lacking. Distally, they narrow evenly down to a short, broad opening often surrounded by a short cylindrical neck. Material: “Thor” 65°52’ N., 23°58’ W., depth 62 metres — 65°02'.N., .13°56;5,W., — rr40 — HYDROIDA II 125 “Thor” 64°02’ N., 22°33’ W., depth 34 metres [labelled Sertularia tenera] — 63°30' N., 20°14, W., — 80 — Iceland: Bakkefjord, — 25—32 fathoms [labelled Sertularza tenera| Faskrudsfjord, _— — 20-50 — Vestmano — 25 = Hvalfjord, — 22 _ [some of the specimens labelled Sertularia tenera| The Faroe Islands: 6 miles N. by W. of Store Kalso, depth 60 fathoms 7 — N. by E. of Myggenes point, — 54 — Vestmanhayn (depth not stated) Glyversnees near Thorshavn ( — - — ) Deep hole at north point of Nols6, depth 100 fathoms 5 miles S.S.E. of Bispen, — 5 — North Sea: 3'/, miles W.'/,S. of Keergaarde beacon, — 15 metres 2 — N. by W. of Vedersé beacon, —18—20 — Kast coast of Southern Jutland (without further details). The study of the present extensive material of Sertwlaria cupressina has shown that variations have played a predominant part in the separation of Sevtularia species. Hincks, in his classic work on the British Hydroids (1868 p. 271) draws distinction between Sertularia argentea and Sertularia cu- pressina on the lines that the former has a more bushy appearance, the latter a more “spire-like apex”, while at the same time the dark stem of the latter species contrasts strongly against the lighter branches. In a large material, however, both these characters are seen to be subject to great variation, and in both respects the two species pass gradually over one into the other. The other distinctive feature is the hydrothece, which are thus described: “The hydrothecee of the cufressima are appressed, tubular, not much narrowed or divergent above, with a bilabiate mouth, while those of argentea are shorter, swollen below, tapering upwards, with the aperture bent, sharply pointed at one side, and oblique”. We need not here dwell on the general form; this is, as will be seen from the figures here given (fig. LXV) highly variable in one and the same branch. More weight should be attached to the fact that the opening in Sertularia argentea is oblique, i.e. furnished with one more and one less prominent tooth. Bonnevie (1899 p. 83) also, in her determinative key, attaches principal importance to this feature, whereas Nutting (1904 p. 62) less happily lays stress upon the remaining features in the hydrotheca. Further investigation, however, soon leads to the conviction that the character is based upon insufficiently careful study. Owing to the strong tendency of the species towards uni- lateral hydrotheca arrangement on the upper branches, the hydrothecee will here be viewed in oblique projection (cf. fig. LXV). Consequently, the outer tooth is seen in its full length, the inner foreshortened in perspective. This is the cause of the oft-mentioned “asymmetry”, which must conse- quently be abandoned as a purely fictitious character. Both the mentioned species are noted in the literature as having the gonothece furnished distally with two lateral points, proceeding as outgrowths from the narrow margins of the gonotheca, 126 HYDROIDA II which is ellipsoidal in section. Even though this form may predominate in many colonies, it is nevertheless far from constant; a very high degree of variation may normally be observed even within a single colony (fig. LXV e—A). We often find, on one and the same branch, gonothece with two points, others with but one, and some with none at all. (This applies, of course, only to acrocyst- bearing, i.e. fully developed, gonothecee; those shown were all provided with acrocysts.) Now while in some colonies the two-pointed gonothecee are numerically predominant, though it is extremely seldom that they are practically supreme, this “normal” form of gonotheca is in the minority in other colonies, where on the contrary the great majority are of the one-pointed type; the entirely spineless a h Z k Fig. LXV. Sertularia cupressina. a Distal hydrothecze of a branch of a colony from the western coast of South Jutland. — 4 Proximal hydrothec from the same branch. — ¢ Distal hydrothecee of a branch of a colony from 6 miles N. by W. of Store Kalsé. — @ Proximal hydrothece of the same branch. — e—g Gonothece from the same colony as a and 6. — h—& Gonothece from the same colony as c and d. ( 40). gonotheca again is not represented to any considerable number in any colony in the material, and must be reckoned as an exception of more or less frequent occurrence. — The mentioned variations in the gonangia throw a doubtful light upon unicarinate forms such as Sertularia Birule Schydlow- sky, where the trophosome, according to the descriptions given, does not differ from that of Sertzda- via cupressina;, the species should doubtless be withdrawn, but as it is not represented in the material, further investigation should be made before the point is decided. After the investigations described, it is impossible to maintain the distinction between Serdz- laria cupressina and Sertularia argentea. The distinction in question, which was originally made from a very restricted material, has since only been retained on the strength of superficial studies, as is shown by the case of the asymmetrically developed teeth above mentioned. And it is just such super- ficial investigations which have led to this superfluity of species into which the genus is still divided. Sertularia cupressina should best be characterised as a boreal species capable of penetrating HYDROIDA Il 127 considerably into the arctic areas, and also southward into warmer seas; it is mentioned from the Mediterranean to Nova Zembla, but the most numerous finds have been made in the boreal region. The species is known from both sides of the Atlantic, and also from the Pacific, which renders its occurrence within the area investigated the more remarkable (fig. LXVI). It is very common in the British waters, and along the west coast of Norway, and is now found to be common also at the Fa- roe Islands and on the east, south and west coasts of Iceland. It has not however, yet been recorded from Greenland, where there would seem every reason to expect it, since it is known from the arctic waters off the east coast of America. The reason of this peculiarity must for the present be left an open question. Sertularia cupressina has its chief occurrence in the upper half of the littoral region, and is only extremely rarely met with in the abyssal. seanee concen cesener 200 mM. Sao soos IOC te tee eee 1000M,~ crasinmce mass onisn 40,0 G)fTTs Fig. LXVI. The distribution of Sertularia cupressina in the Northern Atlantic. In the hatched regions a common occurrence is stated. Sertularia tenera G. O. Sars. 1874 Sertularia tenera, G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 108, pl. 4, figs. 1—4. 1874 Sertularia arctica, Aman, On the diagnosis of new genera and species of Hydroids, p. 179. 1884 Sertularia albimaris, Thompson, The Hydroid Zoophytes of the “Willem Barents”, p. 3, pl. 1, figs. I—3. nec 1877 Sertularia albimaris, Mereschkowsky, On a new genus of Hydroids..... p. 228. 1887 Sertularia argentea + S. Dijmphne, Bergh, Goplepolyper (Hydroider) fra Kara-Havet, p. 335, pl. 28, fig. 3. 1899 Dynamena unilateralis, Bonnevie, Den norske Nordhavs-Expedition, p. 78, pl. 7, fig. 5- rgot Sertularia Thompsoni, Schydlowsky, Les Hydraires de la Mer Blanche. 128 HYDROIDA II The young colonies are always pinnate, the larger ones now pinnate, now with distally sinist- rorse stem. The stem itself is but slightly pronounced, if at all; it is monosiphonic and indistinctly segmented, with almost regularly alternating branches. The branches again produce irregular, not infrequently alternating branchlets, which may further be tertially ramified. The pinnate portions of the colonies have the broad plane of the branches perpendicularly set; in the spirally coiled ones, on the other hand, it is horizontal, On the same side of the stem, or in the same spiral, there are three very rarely two or four hydrothece between two successive branches, the lowest in the branch corner. The branches are divided into irregular internodia with a varying number of hydrothecee. The hydrothece are subalternately to alternately placed; their plane of symmetry coincides, in the pinnate portions, with the broad plane of the branches, but is often much displaced in the spiral parts, so that the hydrotheczee here often come very near to unilateral arrangement on the upper side of the branches. The hydrothecz are not very deeply imbedded, and have a highly diverging distal part; the free distal part of the adcauline wall is almost invariably more than half the length of the hydrotheca, and twice to three times the opening diameter. The maximal breadth is near the middle decreasing thence equally to either end. The aperture margin has two distinct somewhat rounded lateral teeth of equal size; the abcauline large lid plate has a large free distal part. Fig. LXVII. Sertularia te- nera, Part ofa branch witha The gonothece are attached to the branches close under the base of polygonal gonotheca, from the Kara Sea, “Dijmphna”. (X 40). gonothecze are oval, and round or polygonal in section, in the latter case with the hydrothecee; in the spiral part always on the upper side of the branch. The four to six, most frequently five sides; they have distally a broad round opening and an often almost imperceptible tubulous neck. Forma sfitzbergensis: large, spiral and bushy colonies with approach to unilateral arrangement of the hydrothecee. Forma s/b/rica: large, pinnate, slender colonies with no indication of unilateral arrangement in the hydrothece. Material: “Ingolf’ St. 69 62°40’ N., 22°17’ W., depth 589 fathoms 3,9° mor 64°16" N., 22°17’ W., — 50 metres Greenland: Egedesminde, on Soltenia, — 30—50 fathoms Iceland: Hvalfjord, — 22 = The Faroe Islands: 2 miles N.W. of Agraleide, depth 150 fathoms Kara-Sea: “Dijmphna” [labelled Sertularia argentea and Sertularia Dymphne|. Sertularia tenera stands ciearly apart from the foregoing species, and appears to vary some- what less in the shape of the hydrothece. The two geographical varieties are peculiar; the only real distinction lies in the habitus of the colony, and it is not altogether rare to find transition forms, especially in the Murman Sea. We are still, however, unaware as to what factors exert the determin- ative influence upon the shape of the colonies. HYDROIDA II 129 The principal difference, as compared with Ser/wlaria cupressina, is apparent, even in quite young colonies, from the shape of the hydrothece. Sertularia tenera (fig. WXVII) has larger hydro- thece than the mentioned species, and the highly divergent, quite large distal free part gives the colonies a peculiar appearance, very suggestive of Adzetinaria filicula (Ellis et Solander) with which also its dimensions very nearly agree. A character applicable to the larger colonies on the whole is the fact that the main stem in Sertularia tenera does not exhibit any superiority in point of thick- ness over the branches, whereas in Sertularia cupressina it stands out in virtue of its greater dimens- ions; this feature, however, is not always absolutely reliable. — Despite their great variability, the gonothecz also present certain differences as between the two species. The gonothecee in Ser/wlaria COOL Venles ies limelten an 600m. t-+—-—-—-— 000M. ee OOM: ' Fig. LXVIII. The distribution of Sertudaria tencra in the Northern Atlantic. In the hatched region a common occurrence is recorded. tenera are, even where the polygonal form is markedly prominent, never furnished with spines, as is normally the case with Sertwlaria cupressina. Jaderholm (1909 p. 94) suggests the possibility that Dyxamena unilateralis Bonnevie (1899 p. 78) might be synonymous with Zaria arctica (Allman). An investigation of the original specimens fully bears out the correctness of this supposition; the specimens are well developed and entirely typical colonies of Sertularia tenera forma spitzbergensis. Sertularia tenera is an arctic-boreal species having its most frequent occurrence at the limit I s 1 between the two areas; it belongs to the littoral region, and only exceptionally does it move down ) c=) > > ’ into the abyssal. The species has never before been met with at such a depth as at the “Ingolf” St. J I 8 69, and this find must be regarded as a mére accident. Ritchie (1911 p. 218) believes the species to The Ingolf-Expedition. V. 7. 17 130 HYDROIDA II be more common in the Scottish waters than is generally supposed from the data obtained; he con- siders it likely that it may have been confused with young colonies of Sertularia argentea. This sup- position will probably prove correct, as the species is fairly common along the west coast of Norway, and penetrates right down to Bohuslan. It is also not uncommon at the Faroe Islands and Iceland; with regard to the latter locality, it is scarce on the south coast, and apparently not very frequent on the north. From East Greenland, it is known only by a single find far to the north, whereas it has been met with several times in West Greenland waters. (Fig. LXVIII). Sertularia Fabricii Levinsen. 1893 Sertularia Fabricit, Levinsen, Meduser, Ctenophorer og Hydroider, p. 48, pl. 6, figs. 14—17. Upright colonies with not very pronounced, monosiphonic stem, the hydrothecze and branches forming dextrorse spirals. Of the basal branches, only the basal internodium is retained, the remainder falling away. The stem is divided into internodia, each bear- ing a basal branch, alternating in each of the two hydro- theca series; between two successive branches in the same hydrotheca series the stem has normally three hydrothecee the lowest in the branch corner. The broad plane of the branches is horizontally set. The branches are secondarily ramified dichotomically, and divided into internodia of vary- ing length. The hydrothecee are set in two rows, sub- alternately or alternately placed; they are deeply imbedded the free part of the adcauline wall is between one-third and one-sixth the length of the hydrotheca, or between one-half Ee b and one whole opening diameter. The distal part of the hy- Fig. LXIX. Sertudaria Fabricii from Godthaab. drotheca diverges only slightly from the axis of the branch a Hydrothece from the distal part of a branch. Hydrothec from the proximal internodium of On the spiral branches, the hydrothecee tend more or less EXC SERAS | (CCH towards unilateral arrangement on the upper side of the branch. The hydrothecze are of equal breadth in their imbedded part, and narrowing slightly in the free portion towards the opening; the margin of the latter has two short and broad lateral teeth; the abceauline opercular plate has a large free distal part. The gonothecee proceed from below the base of the hydrothecee on the upper side of the branch. They are slender, reversely conical, somewhat flattened in transverse section, the narrow sides as a rule running out each into one short, strong tooth; more rarely, one tooth — or both — may be lacking. The gonotheca has a broad distal aperture, furnished with a short, often rudimentary cy- lindrical neck. “Ingolf? St. 2, 63°04’ N., 9°22’ W., depth 262 fathoms 5,3° - = 3, 63935 N., o°24' W., — 272 _ O5¢ — =" As 164907) (N., 112" Wi. — 237 — Pee Greenland: Store Hellefiskebanke, depth not stated Godthaab, depth 30—4o0 fathoms | Levinsen’s type specimens. Julianehaab, depth not stated HYDROIDA II 131 Jan Mayen, depth 50—60 fathoms (East-Greenland Expedition). Iceland: Mouth of Berufjord, depth 41—54 fathoms. Kara Sea, “Dijmphna”. Sertularia Fabric is very closely related to Sertuwlaria cupressina, but differs primarily in its dextrorse stem. Moreover, its hydrothecze are as a rule more deeply imbedded than in the latter species (fig. LXIX). Levinsen (1893 p. 48) calls attention to a peculiarity in the species, to wit, that the basal branches throw off their extreme parts, leaving only the proximal internodium; this appears to be a characteristic feature in the species, the explanation of which cannot be arrived at from our present knowledge of its biology; it gives the species a highly remarkable appearance. Another char- 200 Mm. a=—o= <= 600M. ‘—--— =—.—.- 1000M., 2000m. Fig. LXX. Finds of Sertularia Fabricéi in the Northern Atlantic. acter which has been emphasised is less reliable; according to Levinsen, the upright direction of the branches is 45° with the longitudinal axis of the stem; but the colonies from Jan Mayen and from the “Ingolf’ St. 2 had branches standing out almost perpendicularly from the stem, and farther out even turning downwards; in these colonies also, the tendency to unilateral arrangement of the hydrothecze is remarkably slight; despite this, and despite the fact that they are of finer build than those from Greenland, they cannot be regarded as types of a distinct species. It is interesting to note how exactly the hydrothece in Sertularia Fabrici follow the same rules in their variation as in Sertwlaria cupressina. On the proximal part of the branches, the hydro- thecze are far more deeply imbedded than at the extremities (fig. LXIX). The gonothece, on the other hand, evince a much slighter variational tendency in the present specimens, which rather give 3 fi 132 HYDROIDA II one the impression that only the extreme — and thus latest developed — gonothece on the branches can lack one or the other of the distal spines. This is different from what we find in Sertularia cu- pressina, where the variants are distributed throughout the whole of the branch, without any distinctly demonstrable regularity. Nutting (1904 p. 71) who mentions the fact that the gonothece in Ser/a- laria Fabricti do vary, has not gone into the question of detail. The recent assignment of a previously undetermined specimen from the Kara Sea to Sertularia Fabricii suggests that we have here a circumpolar species, capable of penetrating somewhat down into the boreal areas. Further investigations will probably show the species to be more common in arctic waters than would appear from the data on record. Sertularia Fabric’ doubtless belongs, strictly speak- ing, to the littoral region, but can, as shown by the finds at “Ingolf” St. 2, 3, and 4, also move some way down into the abyssal. The species has previously been recorded from Alaska and Puget Sound. Within the area investigated (fig. LX X) it is noted from West Greenland, Jan Mayen, and the submarine ridges between Iceland and the Faroe Islands, where the fauna is of a mixed character. Sertularia (?) tubuliformis (Marktanner-Turneretscher) Levinsen. 1890 Dynamena tubuliformis, Marktanner-Turneretscher, Die Hydroiden des k. k. naturhistorischen Hof- museums, p. 238. 1904 Thujaria tubuliformis, Nutting, Sertularide, p. 70, pl. 11, figs. 1—8. 1913 Sertularia tubuliformis, Levinsen, Systematic Studies on the Sertulariidae, p. 298. Upright pinnate colonies with alternating branches. The main stem has, on each internodium, on one side a branch and two hydrothece, on the other a hydrotheca. The branch has in most cases minor branchlets oppositely placed, and is divided by di- stinct segmentation into inter- nodia, bearing two to four, generally three pairs of hy- drothecee, of which the basal ones are the largest, the di- stal being the smallest. The internodium as a whole tap- ers distally. ‘The hydrothecee are set in more or less mark- Fig. LXXI. Sertularia tubuliformis from “Ingolf’ St.1o. edly subalternating, often al- a Part of the colony showing an internodium with its a : : : . most opposite pairs, and are hydrotheca and the basis of two branches. & Gonotheca. (> 40). deeply imbedded. The free part of the adcauline wall is between one-third and one-fourth the length of the hydrotheca, from half to once the opening diameter. The hydro- thecze are of almost equal breadth throughout their length. The opening margin has two large lateral teeth, and a more or less strongly developed median tooth in the adcauline sinus. The closing appa- ratus consists of two membranes, of which the abcauline has a free distal part. HAYDROIDA II 133 The gonothecee proceed from close beneath the base of the hydrothece. They are flattened pear-shaped, with a broad opening on a distally central, trumpet-shaped neck. Material: “Ingolf’ St. to 64°24' N., 28°50’ W., depth 788 fathoms, 3,5°. In point of habitus, this little colony much resembles Dynxamena pumila. Unfortunately, the state of preservation did not permit any further study of the polyps, and it is not impossible that the species may be found to lack the blind sack, in which case, of course, it must be referred to the genus Dynamena. There is no pronounced main stem, and the colony itself rather presents the impression of being only a branch. In all other features however (fig. LXXI) it entirely agrees with earlier de- scriptions, as also with colonies from West Africa, so that its specific identity is beyond doubt. Levinsen (1913 p. 293) notes that the median tooth in this species is of the same length as the lateral ones; this I have not found to be the case in any of the specimens I have been able to examine. The median tooth varies somewhat, and Levinsen’s statement seems to suggést that his material consisted of extreme variants. The finding of this species in deep water so far to the north is highly interesting. In the Atlantic, it was formerly only known from West Africa, and from the tropic-subtropical littoral region of America to the region of Florida. It will probably also prove to inhabit other localities in the deep warm atlantic waters, when sufficient investigations have been made. Sertularia mirabilis (V errill) Levinsen. 1873 Diphasia mirabilis, Verrill, Brief contributions to Zoology, p. 9. 1893 Sertularia mirabilis, Levinsen, Meduser, Ctenophorer og Hydroidetr, p. 49. Upright, robust, pinnate, colonies. The main stem slightly zigzag, monosiphonic, and with two single rows of alternately set hydrothecee. Between two successive branches on the same side of the stem there are three hydrothecz, the lowest in the angle of the branch. The branches have six, more rarely only four longitudinal rows of hydrothecze, the arrangement being produced as follows: three (or two) hydrothecee are set in a wreath at the same height, and the next circle has its hydrothecz facing ‘the intervals of the first. The hydrothecz are fairly deeply imbedded in the stem and branches, with a free part of the adcauline wall only about half the length of the hydrotheca, or between two and three diameters of the opening. The opening margin has two lateral, strongly prominent teeth and an almost rudimentary median tooth in the adcauline sinus. The abcauline closing membrane has a free distal part. The gonothecze proceed from close under the base of the hydrothecz on the one side of the branches. They are pear-shaped to oval, smooth, with a rudimentary neck and broad round aperture. Material: SMito1 61207) IN O730) W., | depth S35.metres Greenland: Kudlisat, Disco (depth not stated) Store Hellefiskebanke, depth 24—32 fathoms. 134 HYDROIDA II Iceland: Adalvig (depth not stated). Kara Sea: “Dijmphna”. Sertularia mirabilis is a circumpolar arctic species, belonging to the upper and middle parts of the littoral region. This being the case, it is remarkable to find it, west of the Faroe Islands, in the abyssal region, as taken by the “Thor” (fig. LXXIJ). Within the waters investigated, Sertularia mirabilis 1s a species of rare occurrence, otherwise found once at the north-west point of Iceland, and high up in Davis Strait off the west coast of Greenland. 200 %. SSS oC OS VOOLD cane eee 1oo0om., iv aseeresomsven sitesi OO Ola Fig. LXXII. Finds of Sertularia mirabilis in the Northern Atlantic. Gen. Hydrallmania (Hincks). Upright colonies with bilateral sessile to slightly imbedded hydrothecee. The hydrotheca aper- ture is furnished with two lateral teeth, between which there is a smaller abcauline and a larger ad- cauline sinus; median teeth lacking. In each of the two sinuses there is fastened a membrane, so that the closing apparatus consists of two membranes, the adcauline with a free distal part. The polyp has a well developed abcauline blind sack. The diagnosis as given coincides with Levinsen’s definition (1913 p. 305); we have here merely added the structure of the polyp body. — Levinsen points out that it may be considered doubtful whether a separation between //ydrallmania and Sertularia really is altogether justified, and the observations noted in the following may to a certain degree serve to accentuate the dubiousness HYDROIDA II 135 of the point. In the northern Serfwlaria species, we find a general tendency towards spiral arrange- ment of the branches, together with an often very marked approach to unilateral arrangement of the hydrothece. The spirally placed branches are secondarily ramified, often dichotomically, but in Sertularta tenera irregularly pinnately. From this then, it is in reality but a short step to Hydrall- mania. And finally, there is a certain amount of variation in the Sev¢ularza species, with regard to proportion between the two sinuses, which in some species may be characterised as of equal size. We have thus, as the last and most essential distinctive feature, the fact that the adcauline closing mem- brane in //ydrallmania has a free distal part, whereas in Sertularia, this is reserved for the abcauline membrane. It may be doubtful whether these small differences should be regarded as of generic im- portance; for the present, however, I have found it most correct to follow Levinsen in distinguish- ing between the two genera. Hydrallmania falcata (Linnué) Hincks. 1758 Sertularia falcata, Linné, Systema nature, Ed. 10, p. 810. 1868 Hydrallmania falcata, Hincks,.A History of the British Hydroid Zoophytes, p. 273, pl. 58. Colonies with slender, spiral, monosiphonic and segmented main stem, where as a rule each internodium bears a branch. The branches form an open spiral about the stem, and are themselves regularly secondarily ramified pinnately; the main stem has a hydro- theca in the corner at the origin of the branch, or may in rare cases be altogether devoid of hydrothecze. Branches and branchlets are segmented, the irregular internodia bear on the one side (the upper) a more or less close row of hydrothece, the opening part of which is turned out alternately to either side from the median plane of the branch. On young pinnate colonies the hydrothecee are imbedded, and alternately placed in two opposite rows on the branches, the broad plane of which stands verti- cally. The hydrothecz are bottle-shaped to tubular, distally often bent, in young colo- nies with biserial arrangement, somewhat imbedded, in older ones with unilateral ar- rangement and almost sessile. The opening margin is armed with two large lateral Fig. LXXIII. Hydralimania falcata from the The gonothecze are oval, as a rule somewhat flattened, with a short tubulous Trondhjem fjord. Part of a branch of a young, pin- teeth, the largest sinus is adcauline, and has a closing membrane with free distal part. ’ neck; they are quite smooth or irregular and slightly furrowed transversely. nate colony of the Material: Sertularia-type. “Ingolf’ St. 6 63°43’ N. 14°34’ W., depth ogo fathoms 7,0° (X% 40): — - 60 65°09' N., 12°27' W., — 124 — 0,9° -- - 87 65°02,3'N., 23°56,2 W., — 110 — os _ - 127 66°33’ N., 20°05’ W., — 44 — Se Shor 66219) NEw 23aca7a We — I1I5—120 metres - (GAH ING, Bs sy We, — 62 — — G4er6! IN. 225072 We, - 500CtC — 64°06’ N., 23°14’ W., - 98 — 136 HYDROIDA II “Thor” 64°o02' N., 22°33’ W., depth 34 metres — G2220HIN.) (2OeTA= WE, — 8 — — 61°07' N., 9°30 W., — 835 — Iceland: Reydarfjord, depth 45—8o0 fathoms Mouth of Berufjord, — 41-54 — Vestman6, — 25-30 — Hvalfjord, = 22 = Bredebugt, 64°45,8’ N., 23°55,2’ W. depth 30 fathoms Stykkisholm, — 30 - 6 miles W. of Iceland, 65°32’ N., 24°38’ W., depth 22 fathoms Talknafjord, depth 22 fathoms Dyrafjord, — I5 ~ Onundarfjord — _ to — Adalvik (depth not stated). The Faroe Islands: 6 miles N. by W. of Store Kals6, depth 60 fathoms 7 — N. by E. of Myggenes point — 57) — 12 — N.W. of Agraleide, — 150 — Deep hole at north point of Nols6, — 100 — Szemundsson (1911 p. 92) briefly mentions that the branches in young colonies of //ydradl- mania falcata are at times short, unbranched, and biserial, and that the same is often the case with the basal branches in somewhat larger colonies. Levinsen also (1913 p. 308) mentions small pinnate colonies of 29 mm length from Hellebeek, Denmark, but without quoting further details as to the hydrothecee. The frequent occurrence of the species in the Trondhjem Fjord has afforded an opport- unity for closer study; the colonies are often very finely built. Young colonies of /ydrallmania falcata may at times even at a length of 5 cm be singly pin- nately branched, and it is then extremely difficult to distinguish them from Serfezdaria. The stem, which is here, of course, not yet spiral, has a hydrotheca at the base of each branch, a feature which is likewise common in larger colonies from the Trondhjem Fjord, and which I have found in most of the other colonies investigated from our seas. The hydrothecee on the branches in young colonies, as also those on the branches in the pinnate basal parts of older ones, are arranged in two opposite rows (fig. LX XIII) in such a manner that the symmetrical plane of the hydrothecze coincides with the vertically set broad plane of the branches; the hydrothecze on these branches are alternately set, and with quite a considerable interval between. The distal half, or more, of the adcauline wall is free; the length of the free portion is from once to twice the diameter of the opening. Quite young colonies are thus extremely liable to be confused with small Sertu/arza colonies, unless the hydrothecz are very carefully examined. The adcauline sinus in Wydralimania is normally deeper than the abcauline; the difference is, however, at times very slight, and if the closing membranes have fallen away, it is very difficult to identify the colonies. When the colonies are somewhat larger, the spiral coiling of the stem begins to make its HYDROIDA II 137 appearance at the top. And at the same time, a marked change takes place in the branches, which now turn go° on their axis, so that their original broad plane becomes horizontal; further, a displace- ment of the hydrotheca towards the upper side of the branch also sets in, and the typical unilateral arrangement usual in the species now becomes apparent. Soon the bases of the hydrothece form a single row, and only the oral part is turned or bent out alternately to either side of the median plane, as a last trace of the biserial structure. Gradually also, secondary ramification takes place, the primary branches throwing out secondary branchlets, directed alternately to either side in the primary broad plane of the branch. In the -more finely built colonies, the main branch has three, or more rarely four hydrothecee between two branchlets; in colonies of coarser build, on the other hand, the number is only exceptionally as low as three, and as a rule we find four or more hydrothece between the origins of two secondary branches. The features here mentioned are of importance in several respects. In the first place, they show that Hydrallmania colonies agree entirely in their mode of development with the remaining Sertulariide having spiral stem, as far as this has been studied and described; they prove also, that the Hydrallmania colony, which at, the first glance appears so entirely distinct, can be easily traced back to the typical colony in Sertularia tenera or Thoyaria thuja. In the second place, the features in question reveal a striking resemblance between finer colonies of Hydrallmania falcata and Hydrall- mania distans Nutting from Puget Sound; the likeness is so great that we are tempted to note them down without further consideration as synonyms, or rather, to regard the specimens from Trondhjem Fjord as belonging to the latter species. It would, however, be highly remarkable that this Pacific species should occur here and not elsewhere in the Atlantic. And closer study now shows that the Trondhjem Fjord type is not isolated, but is related, through every possible transition type, to the close and robust form which is predominant in the open sea, and which has always been taken as the type for Hydrallmania falcata. It is interesting also to note that several colonies in the material, as for instance some from Berufjord, have in among the lower normal branches one or two others of the Sertularia type. Elsewhere in the material we also find small colonies from several places agreeing with the young form from the Trondhjem Fjord, only of coarser build. Nutting (1904 p. 126) notes as a distinctive character between Hydrallmania distans and Hydr- allmania falcata that the latter species lacks hydrotheca on the stem at the base of the branch. This is, however, exceptional. The hydrotheca on the stem at the base of the branch may at times, especially in older colonies, be lacking, but in most cases it is to be found, and is always present in the somewhat smaller colonies. Nor can the difference mentioned by Nutting as existent in the gonothecze be accepted as a specific character; it lies well inside the limits of variation observed in a single fairly luxuriant colony of Aydrallmania falcata. That I nevertheless refrain from definitely withdrawing Hydrallmania distans is due to the fact that my collections include no material of the species in question, and I am thus unable to determine whether possibly some characters not mentioned in Nutting’s diagnosis might be found, sufficient to warrant specific distinction. The other American Pacific species also, Hydrallmania franciscana (Trask), calls for thorough investigation, its raison d¢tre being likewise highly problematical. The available drawings and data for the two species are not enough to decide the question. The Ingolf-Expedition. V. 7, 18 138 HYDROIDA II Hydralimania falcata has its chief occurrence in the littoral region of the boreal seas, and may exceptionally penetrate deeper down into the abyssal, where it has, however, once or twice been ob- served at 2000 metres depth. The species can move right up into arctic waters, and has even been met with in the Kara Sea; otherwise, its occurrence coincides with the presence of warmer currents in the high arctic areas. It may also penetrate some distance to the southward, as is shown by its more sporadic occurrence in the Bay of Biscay. In the North Atlantic also, it has been found off the east coast of America. It is thus the more surprising that it should never have been recorded from Greenland (fig. LXXIV) as it is one of the most common of all species in Iceland waters; on the west and east coast especially, the finds were so numerous that it was impossible to note them all on the 200 m. Soo.c 55,000 ta tae eee 1000 Mm, Fig. LXXIV. The distribution of Hydrallmania falcata in the Northern Atlantic. In the hatched regions the literature notes a common occurrence. chart. On the north coast of Iceland, Hydvallmania falcata is quite sporadic in its occurrence, and is not particularly numerous on the south coast. Between Iceland and the Faroe Islands, and on the northern side of the latter, it is again fairly numerous, while in the North Sea area and along the coast of Norway it appears as a character form. Gen. Thujaria (Fleming). Upright colonies with imbedded hydrothece. The hydrothece are of bilateral structure; the aperture is furnished with an abcaulinally fixed single opercular plate or membrane, attached to the margin of the hydrotheca, as a rule in a more or less pronounced sinus. The polyp has an abcauline strongly developed blind sack. HYDROIDA II 139 Thujaria thuja (Linné) Fleming. 1757 Sertularta thea, Linné, Systema nature, Ed. 10, p. 809. 1828 Thwaria thuja, Fleming, A History of British Animals, p. 545. Upright colonies, shaped like a bottle-brush, with dark-coloured, distinct monosiphonic hydro- caulus. The branches form an irregular, close double spiral round the indistinctly segmented stem, one branch to each joint. The stem has two rows of hydrothece; there are normally three hydro- thecze on the stem between two successive branches in the same row, the lowest in the branch corner. The branches form, at their point of origin, almost a right angle with the stem, and are repeatedly divided dichotomously, and curve slightly upward. They are segmented, with a large and varying number of hydrothecze on each joint. The hydrothecee form two opposite rows on the branches; their plane of symmetry coincides with the broad plane of the branch, which is horizontal. The hydrothecc are entirely imbedded in the branches, with no free portion of the adcauline wall; they are subaltern- ately arranged; at the top of the branch they have two lateral teeth, but in course of growth the ad- cauline sinus fills up, normally altogether. The interval between two successive hydrothecz is about twice the opening diameter of the hydrotheca. The operculum is formed by a round plate abcaulin- ally attached. The gonothece are situate on the upper side of the branch, and proceeding from close under the base of the hydrothece. They are oval, without ribs or wrinkles, with a short neck and broad round aperture. Material: “Ingolf’ St. 2, 63°04’ N., 9°22’ W., depth 262 fathoms, 5,3° _ SB atAG ING, IOFeA Nile — 272 — 0,5" — = fil (ouitoy/ INI, ees Wig, — 237 — DSS — = i, fats! ING, BE EG! Wo, — 330 — +0,75° STC NOSE ae 54k ave ee 55th = - = Ste OACrS ON. k422) W., — 68 -- Te — - 87, 65°02,3'N., 23°56,2’W., — 110 a — — MOS NOS nA IN: 630239, Wo, i. 752 ~ Aa = - 96, 65°24' N., 29°oo' W., e725 -- 1 _ - 98, 65°38’ N., 26°27’ W., — 138 _ 59° — =I 527 |OO333/e NE 2OrO5) W., — 44 a 1,6° “Thor” GOST IN 2327aNVE, — 115—120 metres os 63°46’ N., 22°56’ W., — 150 — Greenland: Davis Strait, depth 66—67 fathoms (without further details) Iceland: Seydisfjord, — 40 — 5 miles E. of Seydisfjord, depth 135 fathoms Reykjavik (d2pth not stated) 6 miles W. of Iceland, 65°32’ N., 24°38’ W., depth 22 fathoms Danmark Strait 65°39’ N., 28°25’ W., (depth not stated) 140 HYDROIDA II Iceland: Danmark Strait 66°20’ N., 25°12’ W., depth 96 fathoms Adalvik, depth 5,5 fathoms (on roots of Laminaria). The Faroe Islands: 6 miles N. by W. of Store Kals6, depth 60 fathoms Vestmanhayn (depth not stated) Deep hole of north point of Nols6, depth roo fathoms 16 miles E. by S. of south point of Nolsd, depth 80 fathoms Borones 13 miles N.75 W., depth 30 fathoms. Quite young colonies of 7hawjaria thaja are pinnate, and very difficult to distinguish from small colonies of Zhajaria laxa Allman. The broad plane of the branches in such specimens, up to a couple 200 m, orn a esmstimatfesh OCA OMA, Fig. LXXV. The distribution of 7hujaria thuja in the Northern Atlantic. In the hatched regions a common occurrence is recorded. of centimetres high, is vertical, and the branches are single. Here, however, the hydrotheca at the tip of the branch, which is of the Serfularia type, will as a rule reveal the identity of the species. The occurrence of this type of hydrotheca in 7heyaria thuja is, as I have previously pointed out (1905) of considerabie interest, as giving us a hint of the derivation of the Zhejarza species from Sertularia. Thjaria thuja is a boreal species, capable of moving far to the south; it is said to have been found both off the coast of Portugal and in the Mediterranean, but is not common south of Ireland. On the other hand, it does not enter the purely arctic waters; it has its chief distribution in the deep littoral region, but may occasionally be met with in the abyssal, and even deep down in the same, as is seen from the finds of the “Ingolf’ at St. 95 and 96. In the North Atlantic (fig. LX XV) the HYDROIDA II I41 species is rare off the west coast of Greenland, and appears to be altogether lacking on the east coast. In Iceland waters, it is frequent on the west coast, and in Danmark Strait, and is also common on the east coast; common on the ridge between Iceland and the Faroe Islands, and around the latter Islands. In the North Sea, it is one of the most common species, and occurs also as a common form along the coast of Norway right up to the North Cape. Thujaria sp. aff. hippuris Allman. From the “Ingolf” St. 24 (63°06’ N., 56°00 W., depth 1199 fathoms, 2,4°) we have some colonies of a Thwaria, the identity of which cannot be determined with certainty. The colonies are slenderly pinnate, with branches openly set; the stem is very slightly pronounced, and in colonies ro cm. high shows incipient spiral coiling at the top; the broad plane of the branches here assumes a horizontal position, while elsewhere it is always vertical. The branches form almost a right angle with the stem. The stem has two rows of hydrothecee, and is divided into internodia bearing as a rule four branches, two to either side, alternately placed. There are three hydrothecz between two successive branches on the same side of the stem, the lowest in the branch angle. The branches are irregularly segmented, with two to five, or rarely more, hydrothece on the internodium. The hydrothece are set in two rows on the branches; their plane of symmetry coincides with the broad plane of the branches; they are alternately placed on the slightly zigzag branches (and stems) and separated, in the same row, by intervals exceeding the length of the hydrotheca (fig. LXXVI). The hydrothecee are deeply imbedded, and have a short free distal part of the adcauline wall; the length of this is at the outside half the opening diameter. : . Fig. LXXVI. The hydrotheca opening is round, with an even margin, and no indication of teeth or ijariasp. aff. hippuris. Part sinus; there is a large round opercular plate abcaulinally fixed. The colonies are unfor- of a branch. tunately all sterile, with no indication of gonangia formation. (X 40). The colonies described appear in their general features to present some considerable likeness to 7w- jaria hippuris Allman, but are even more slender and with more widely set hydrothecee than noted for the species in question (cf. Allman 1874, p. 473, pl. 45 fig. 2, and Kram p 1913, p. 26). The shape of the colony in Thujaria hippuris is very nearly the same as in Zhzyaria tha. The largest colonies in the material show that the present species would also probably be of the same form when fully grown; the pinnate arrangement of the colonies, and the lack of secondary ramification in the branches, can therefore only be regarded as juvenile characters. The slight specific differences otherwise existing in the genus 7/zyaria call, how- ever, for caution. The hydrotheczee in the colonies here concerned are not entirely imbedded, as is otherwise stated to be the case with Zhejaria hippuris, but have a very short free distal part on the adcauline side; there is also a wider interval between the hydrothece in the same row, and the bran- ches are bent slightly zigzag fashion. These points render it somewhat doubtful whether the spe- cimens in question really belong to Zhwaria hippuris, and the identity cannot be determined with certainty until the variational conditions of the species in question have been further elucidated. The enormous depth at which the colonies occur is very interesting, and will possibly serve to explain its extremely slender form. 142 HYDROIDA II Thujaria laxa Allman. 1874 Thwaria laxa, Allman, Report on the Hydroida..... “Porcupine” "p: 472, ple-45, figs 1 1895 Zheyaria lonchitis, Marktanner-Turneretscher, Hydroiden yon Ost Spitzbergen, p. 422. 1903 Thwaria Hyorti, Broch, Die von dem Norwegischen Fischereidampfer “Michael Sars” ..... ge- sammelten Hydroiden, p. 7, Taf. III, figs. r1—14. 1904 Thujaria immersa, Nutting, Sertularidae, p. 66, pl. 9, figs. 3—4. The upright colonies are as a rule pinnate in their lower parts, spirally curved in the upper, and with slender, secondarily dichotomously ramified branches, forming an open double spiral around the distinct main stem, which is somewhat darker in colour. In the pinnate portion, the broad plane of the branches is vertical, in the spiral it is horizontal. The stem has two opposite rows of hydro- thecee; there are as a rule 4 or 5 hydrothecee between two successive branches on the same side (or in the same spiral), the lowest at the corner of the branch. The branches form almost a right angle with the stem, and are very nearly straight; they are irregularly segmented with a large number of hydrothecze on each internodium. The hydrothecz are set subalternately in two rows on the bran- ches; their symmetrical plane coincides with the broad plane of the branch. The hydrothece are en- tirely imbedded, or have a very small free distal part of the adcauline wall, never more than half the opening diameter. The interval between two successive hydrothecee in the same row is as a rule about equal to or slightly more than the opening diameter. The hydrotheca opening is round, the margin without any indication of teeth or sinus, and has a round opercular plate abcaulinally attached. The gonothece are situated on the upper side of the branches close under the basis of the hydrothece. They are oblong, narrow pear-shaped, the male distally cut off transversely, the female more rounded, without neck. Material: “Ingolf St. 3 63°35’ N., 10°24’ W., depth 272 fathoms 0,5° — = 15 (06°18 N., 25259) W., — 330 = SS OWS: = = 32 66535; IN. 50°38" W,, — 318 | — eho Soa A OS Le NG 57 S\N mS iat =) <5 445 6142" N. 9°38" Wa, 8) 545) 2 es _ = pu ovis! INE ae! Wir. — 68 _ 7,320 -- - 87 65°02,3'N., 23°56,2°W., — IIo — _ — - 94 64°56' N., 36°19' W., — 204 _ Alan — - 98 65°38' N., 26°27’ W., — 138 — 59° Greenland: Turner Sound, — 120 — Cape Tobin, — 7 — (Kast Greenland Expedition) Off Henry Land, — 20 — — — — Off Henry Land, — 160—200 — — = = Between the Faroe and the Shetland Islands, depth 255 fathoms. Kara Sea, “Dijmphna” [labelled Zhejaria lonchitis and Thyarta articulata). Thyaria laxa belongs to the lower parts of the littoral region, and the upper part of the abys- sal. It is an arctic species, which has been found from Davis Strait to Tajmyr; it is also represented HYDROIDA ITI 143 in the material from the cruise of the “Dijmphna” in the Kara Sea, but has there erronously been referred either to Zhejaria lonchitis or Thwyaria articulata. From its arctic home, the species also spreads out into the boreal region (fig. LXXVII) where it has been recorded from the Faroe Islands and Iceland, and in Davis Strait. It will presumably also be found to occur off the coast of Norway, but in these waters, it has not hitherto been distinguished from Zhzyarza lonchitis, so that we have no reliable data up to the present. ecesiocmotcecorenec 200 m. ators a tOlOO1NT: tases sass. 000M, Bees ieee 2 OOO MT. Fig. LXXVII. Finds of Zhwaria /axa in the Northern Atlantic. Thujaria alternitheca Levinsen. 1893 Thujaria alternitheca, 1evinsen, Meduser, Ctenophorer og Hydroider, p. 52 pl. 7, figs. 15—20. Robust, upright colonies with spiral, monosiphonic stem. The stem is divided by distinct seg- mentation into internodia of varying length, and has two single spiral tiers of hydrothece; there are from 3 to 6 hydrothecze between two successive branches in the same spiral, the lowest in the branch corner. Normally, the sixth branch will be found straight above the first in the same tier. The broad plane of the branches is perpendicular to the axis of the stem (lies horizontally) and the branches form, at their point of origin, almost a right angle with the stem, afterwards curving somewhat downwards; they are secondarily branched dichotomously, and divided into internodia with five or more pairs of hydrothecz. The hydrothece of the branches form two very close longitudinal rows; the hydrothece are closely set, each thrusting its opening part out upwards and sideways beyond the next, displaced alternately to either side of the median line through the base of the hydrothecz, presenting a distinct approach to quadriserial arrangement. The hydrothece are entirely imbedded in the stem and bran- ches, without any free distal part of the adcauline wall. The opening is circular, the margin without teeth or sinus, with a large round opercular plate abcaulinally attached. 144 HYDROIDA II The gonothecee are set on the upper side of the branches. They are pear-shaped, with rudi- mentary neck and broad aperture. Material: “Ingolf’ St. 31 66°35' N., 55°54’ W., depth 88 fathoms 1,6° BA MOS NSA) Wie OS = Greenland: Davis Strait, — 100 — (without further details) [type specimen]. Iceland: Skagi, — 20 — [labelled Zhajaria lonchitis| Dyrafjord, — 5 — In all probability, this species also will prove to have a pinnate development stage, like the other, spiral Zheyarza species. In the arrangement of the hydrothecee, 7hwjaria alternitheca forms a parallel to Adzetimaria (?) fusca (Johnston), and it is interesting here to note how the hydrothece, owing to their extremely close accumulation, thrust their opening part to one side or the other from the base of the next following. An investigation of the tip of the branch shows that this is a secon- dary phenomenon. The hydrothece are to begin with symmetrically situate, with their symmetrical plane parallel to the branch axis; only on the formation of a new distal hydrotheca is the aperture of the one behind it thrust out to the side. We have here, then, a typical instance of convergency, as towards A bretinaria (?) fusca, which cannot be taken as evidence of closer relationship, and thus does not afford any justification for uniting the two species mentioned, and other multiserial forms in a special genus Se/aginopsis; any such would also have to include species with and those without blind sack, which can hardly be considered permissible. dec nares 200 m. Se I ACL Mae sashes fara FOOOUMs Nastaesseetrnmees 2000.19 Fig. LXXVIII. Finds of Thwarta alternitheca. HYDROIDA II 145 Thwaria alternitheca is probably an arctic species of highly localised occurrence. It belongs to the deepest littoral waters. Previously, it was only known from Davis Strait, but is now found to occur also off the west coast of Iceland, where it has been confused with a form of much finer build, Thyaria lonchites. Thujaria variabilis nov. nom. 1899 Selaginopsis arctica, Bonnevie, Den Norske Nordhavs-Expedition, p. 87, pl. 6, fig. 4. Coarse, upright pinnate colonies with undivided branches. The stem is slightly zigzag, divided into internodia of irregular length, with from two to twelve regularly alternating branches and two single rows of hydrothecze; the stem is not spirally coiled. The stem has from two to four, normally three, hydrothecze between two successive branches on the same side, the lowest in the branch angle. The branches have four, exceptionally two or three, rows of hydrothecze; on the four-rowed branches, the hydrothecze are set in opposite pairs, the symmetrical plane of the one pair being then perpendi- cular to that of the next; three-rowed branches are spirally coiled, two-rowed straight, with the sym- metrical plane of the hydrothecze vertical. The hydrothecze are broad and deeply imbedded, with a short, often quite insignificant free distal part of the adcauline wall, never more than a third of the opening diameter, or one-tenth to one-twelfth the length of the hydrotheca. The opening is round, with smooth margin, without teeth or sinus, and has a large opercular plate abcaulinally fixed. The gonothecze are set on the upper side of the branches, and proceed from close below the base of the hydrothecee. The gonothecz are inversely conical, distally cut off transversely, without neck. Material: Iceland, Reydarfjord, depth 80 fathoms (some of them labelled Zheyaria lonchitis). A number of very fine colonies belonging to this species have been incorrectly determined by Semundsson as Thyaria lonchitis, from which Theyaria variabilis is immediately distinguish- able by its extremely robust appearance and thick branches. The colonies are interesting in several respects. They show, in the first place, that aberrant branches with fewer than four hydrothecz rows are by no means rare, and in the second, that the number of hydrothece rows on a branch may vary from one internodium to another. There are thus some branches which are basally quadriserial, distally bi- or triserial; others again are biserial, triserial or quadriserial throughout their entire length, or only quadriserial at the extremities. This feature, then, is subject to great variation. It is also remarkable that biserial branches are straight, whereas the triserial, and exceptionally also the qua- driserial, are twisted, so that the hydrothecz here lie in very steeply ascendant spiral tiers about the branches. The normal quadriserial branch on the other hand, presents a compressed Stawrotheca type, where the single hydrotheca pair is revolved as against the preceding pair, and has its plane of symmetry perpendicular to that of the latter; this also gives very close spiral lines in the arrange- ment of the hydrothece, as pointed out by previous investigators. The species, with its variations, gives a drastic exposure of the value attaching to the distinctive characters for the genera Svawro- theca and Selaginopsis. It is evident from the foregoing that Selagimopsis artica Bonnevie must be classed under the The Ingolf-Expedition. V. 7. 19 146 HYDROIDA II genus Z/eyaria, as I have already (1909 p. 222) placed it. The same genus, however, has formerly been made to include Serfularia arctica Allman and Sertularia arctica Thompson, which is incorrect. The proper method of proceeding here will be to alter the name of the present species, as being of later date, and this I have accordingly done, naming it, from the variable character of the branches, Thyaria variabilis. Thuyarta variabilis has only occasionally been found in arctic waters near Beeren Island, at Spitzbergen and off the Murman Coast at 38 to 86 metres’ depth. Reydarfjord thus represents the most southerly find, and is also, with its 80 fathoms, the deepest. Thujaria lonchitis (Ellis and Solander) Fleming. 1786 Sertularia lonchitis, Ellis and Solander, The natural history of many curious and uncommon Zoophytes, p. 42. 1828 Zheyaria articulata, Fleming, A History of british animals, p. 545. nec 1766 Ser/ularia articulata, Pallas, Elenchus Zoophytorum, p. 137. 1847 Zhiyaria articulata, Johnston, A History of the British Zoophytes, p. 84, pl. 18, figs. 3—4. nec1851_ — “= Busk, A list of Sertularian Zoophytes and Polyzoa from Port Natal, Algoa Bay ease Palos 1868 — _ pars, Hincks, A History of the British Hydroid Zoophytes, p. 277, pl. 60. 1874 — — G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 106. 1884 — lonchitis, Kirchenpauer, Nordische Gattungen und Arten von Sertulariden, p. 24, pl. 14, kee, GE (nec1884 — articulata, Kirchenpauer, l.c. p. 26, pl. 14, fig. 8) nec1888 — fectinata, Allman, “Challenger” vol. 23, p. 69, pl. 33, fig. 1. 1890 — lonchitis, Marktanner-Turneretscher, Die Hydroiden des k. k. naturhistorischen Hof- museums, p. 2 36. 1893 — - Levinsen, Meduser, Ctenophorer og Hydroider, p. 53. 1899 — articulata pars, Bonnevie, Den norske Nordhavs-Expedition, p. 84. 1904 — lonchitis, Nutting, Sertularidae, p. 66, pl. o, figs. 5—8. 1909 — kolaénsis, Jaderholm, Northern and Arctic Invertebrates, p. 88, pl. 8, figs. 17—18. ?1g09 — lonchites, Jaderholm, 1. c. p. 89, pl. 9, fig. 3. 1909 — -—- 3roch, Die Hydroiden der arktischen Meere, p. 174. The upright colonies are as a rule pinnate throughout their entire length, more rarely with a spirally coiled distal part of the monosiphonic stem. In the pinnate portion of the colonies, the broad plane of the branches is vertical, in the spiral horizontal; the branches form almost a right angle with the stem, which is dark in colour. The stem is segmented in its lower part, but in the upper, the segmentation becomes almost entirely effaced; the branches are subalternately to alternately set. The stem has two rows of hydrothece; between two successive branches on the same side of the stem there will be two to three, rarely more (up to five) hydrothecee, the lowest in the angle of the branch. The branches are not generally ramified, but may more rarely exhibit secondary dichotomous ramifi- HYDROIDA II 147 cation; they are divided into irregular internodia with a large and varying number of hydrothece on each. The hydrothecee are alternately or subalternately set in two opposite rows on the branches; their symmetrical plane coincides with the broad plane of the branch. The hydrothece are deeply imbed- ded; the adcauline wall has a free distal part between half and once the opening diameter or between one-eighth and one-fourth the length of the hydrotheca itself. The hydrotheca opening is round, the margin as a rule having a more or less distinct abcauline sinus, so that the hydrotheca aperture often appears furnished with two sligtly prominent teeth. The distance between two hydrothecz in the same row is very slight, less than half the opening diameter. The operculum is formed by a large opercular plate abcaulinally attached. The gonothece are set on the upper side of the branches, and proceed from close under the base of the hydrothece. They are narrowly pear-shaped, with a short, often almost rudimentary cy- lindrical neck, and broad aperture. Material: “Ingolf St. 44 61°42’ N., 9°36’ W., depth 545 fathoms, 4,8° _ -144 62°409' N:, 7°12’ W.. — 276 — 1,6° Greenland: Davis Strait, — 80 — _ (without further details). The synonymy of this species is extremely difficult to determine; we are to a great extent forced to rely on geographical data) Kirchenpauer (1884) was really the first to point out what particular characters distinguish the two species which have been taken together under the name of Thwyaria articulata; to him belongs the credit of having given the definite characterisation of that South Sea form for which he has — doubtless correctly — reserved the name Zhzyaria articulata (Pallas). This is specifically quite different from the northern species which has been given the same name, but which should properly be known as Zhzyarta lonchitis (Ellis et Solander). That the two have hitherto been so generally confused is due partly to the fact that writers have relied upon the records in the extant literature, partly to the frequent inability on the part of investigators to procure material of more than the one species. Thus it happens also, that even Bedot, in his brilliant work: “Matériaux pour servir 4 l’histoire des Hydroides” has committed the error of noting the two species as synonyms, despite the fact that the drawings given by Hincks (1868), and Allman (1888) could hardly be regarded as illustrating the same species. Stechow (1913 p. 152) and Broch (1914 p. 34) have, after further study of both species, given a closer definition of Zhzyarta articulata, from which, and from the descriptions given of Z/eyarta lonchitis, it is evident that they differ even more than is usual between other species of the genus in question. Thyarta lonchitis appears to be an arctic circumpolar species, which may penetrate into the boreal areas. But as it has constantly been confused with related forms, especially with TZheyaria laxa, its geographical character cannot be defined with certainty. From the list of material for the remaining northern species, we see that it has also in the waters here investigated constantly been confused with other Zheyaria species, and it will therefore be most correct to leave the final decision as to its biogeographical position in abeyance, pending the acquisition of new and more reliable data. 1g 148 HYDROIDA II Thujaria carica Levinsen. 1893 Theyarta carica Levinsen, Meduser, Ctenophorer og Hydroider, appendix, pl. 7, figs. 26--29. The upright colonies are pinnate in their basal parts, spirally coiled in the distal, with bran- ches secondarily somewhat ramified dichotomously; the symmetrical plane of the branches is vertical in the pinnate parts, but horizontal in the spiral. The stem has two single, opposite longitudinal rows of hydrothecze; there are two to five, generally three hydrothecze between two successive branches on the same side ofthe stem, the lowest in the branch angle. The branches are divided into irregular inter- nodia with four to eight hydrothecze on each; the hydrothece are set subalternately in two opposite longitudinal rows, their plane of symmetry coinciding with the broad plane of the branch. The hydro- thecze have a large free distal part; the length of the free portion of the adcauline wall exceeds the diameter of the opening, and is between one-third and one-half the length of the hydrotheca itself; the opening margin is smooth, without sinus, with a round opercular plate abcaulinally fixed. The interval between two hydrothece in the same row varies somewhat, but is never Jess than the opening diameter. The gonothecze are set on the upper side of the branches in the spiral parts of the colonies. They are asymmetrical oval to pear-shaped, with a rudimentary neck and broad, round opening. Material: “Ingolf” St. 143 62°58’ N., 7°09’ W., depth 388 fathoms, + 0,4° “Thor” 66°19’ N., 23°14’ W., depth 115—120 metres [labelled Zheyaria lonchitis]. Iceland: 32 miles S. of Selvogstangar, depth 170 metres. Kara Sea “Dijmphna” [type-specimen]. Thwaria carica is an arctic species known from the waters between Spitzbergen and Beeren Island to the New Siberian islands; in the high arctic tracts it belongs to the upper third of the littoral region. South of the range mentioned, the species has hitherto only been found at the south- west point of Iceland, and north of the Faroe Islands, where it moves down into the abyssal region. Up to now, it has not been recorded from Greenland, and thus appears. to be an easterly arctic species. Thujaria sp. aff. distans Fraser. Material: “Ingolf St. 85, 63°21’ N., 25°21’ W., depth 170 fathoms The small 7heyaria colonies from the “Ingolf” St. 85 very much resemble 7hewaria carica, and may possibly prove to belong to that species; there are, however, certain points of difference which render the identity somewhat doubtful, and for the present, these colonies should doubtless be kept apart from Thwaria carica. It is not unlikely that they really represent a distinct species, but as the colonies are quite small, and without gonangia, it is very difficult to give a thorough characterisation. The colonies are pinnate, with simple branches. The stem, which is monosiphonic, is divided into irregular internodia, and lacks both branches and hydrothecze on its lower part. A couple of centi- metres from the base, the hydrothecze begin to appear; they are set as a rule alternately in two op- posite longitudinal rows. The stem is slightly zigzag, and has on its upper part, besides the hydro- thecee mentioned, also alternating branches; the largest colony which is of quite regular build has HYDROIDA II 149 throughout three hydrothecee between the origins of two branches on the same side of the stem; in the two smaller colonies, on the other hand, the number varies from two to five, but these colonies are at the same time irregular in the whole development of the branches in several places. The divi- sion of the branches into internodia is highly irregular; there may be from two to nineteen hydrothecze on the branch internodia. The hydrothecze are set in two opposite rows; their symmetrical plane coincides with the broad plane of the bran- ches, which is everywhere vertically placed, i.e. parallel with the axis of the stem. The distance between two. hydrothecee on the same side of the branch is very great, as a rule about 1'/, times the length of the hydrotheca itself. The hydrotheca (fig. LXXIX) is not particularly deeply imbedded in stem or branches; the distal third of the adcauline wall is free; the free part of the adcauline wall is straight, or not infrequently curving slightly upward. The opening plane of the hydrotheca is pa- rallel with the branch axis. The aperture is round, the margin exhibits indication of a pair of broad lateral teeth, further accentuated by the abcauline sinus in which the large single opercular plate is fastened. The structural character of the polyp it was impossible to investigate, owing to the state of preservation of the material. These colonies appear in the main to agree with the Pacific species Theyaria distans established by Fraser (1914 p. 197, pl. 32, fig. 123). There are, however, lacune in Fraser’s description, so the identity cannot be determined with certainty. Fig. LXXIX. Fraser’s species has often secondary dichotomous ramification of the branches; 7”ya77asp. aff. distans : E 5 f from “Ingolf’ St. 85. this must be considered as due to difference in age. On the other hand, the hydro- part of a branch. thecee in Zheyaria distans appear to have a larger free portion; Fraser states (X 40). “about one-half free”, and the figures appended, which are not very carefully drawn, even show hydro- thecze more than half free; they give, moreover, no clear impression as to the character of the hydro- theca aperture, which is likewise somewhat vaguely treated in the diagnosis: “margin without distinct teeth but rather bilabial”. Only when a conscientious description of the Pacific species is available will it be possible to decide whether the colonies here found in the North Atlantic should be referred to the same. Family series Proboscoida (Broch). Family Campanulariide. The hydrothece are radially symmetrical, bell-shaped, without closing apparatus, and provided with a basal chamber separated off from the distal main part of the hydrotheca by a diaphragm, or by a simple ring-shaped thickening of the wall. The polyps can withdraw entirely into the hydro- thecee. The hydranth has a club-shaped proboscis, attached by a narrow base to the body of the polyp above the tentacle crown; the gastral endoderm is homogeneous, the stomach part not divided into separate regions. The colonies are stolonial or sympodial. 150 HYDROIDA II The diagnosis of the family as here given excludes the two bilaterally built genera Sz/zcolaria and Eucopelia; these two genera should, partly on account of their being bilateral, partly also from their peculiar, almost leathery hydrothece, and the small size of the latter, which can only accomodate the basal part of the contracted polyp, be separated off as a distinct family Svzdecwlaride@, as I have pointed out already in a former work (1909). Nutting, in his latest work on Campanularide (1915) still treats the two families as one, though he gives no reason for so doing’. The Campanulariude, as here defined, make up a well marked family which can hardly be the subject of much dispute; the generic sub-division of the family, however, is a highly debatable question, and a study of the literature thereupon affords an interesting example of the extent to which, even at the present day, it is found “convenient” (i. e. less troublesome), or “advisable” to persevere in the adherence to earlier tradition, or acceptance of biological phenomena, in dealing with the great group of the Hydroids. This is in fact the obstacle which for years has barred our progress towards an understanding of the group in question, its development, and the various degrees of relationship be-) tween its subdivisions. — I have in a previous work (1909) explained at length why, in the northern waters, it is only permissible to recognise two genera of Campanulartide from a phylogenetic point of view, to wit, Campanularia and Laomedea. The description of Laomedea sargasst (Broch 1913 p. 3) does not weaken this standpoint. Nutting, however, opines (1915 p. 24) that “while there may be considerable argument on theoretical grounds for such a course, it undoubtedly leads to unneces- sary and practically insurmountable difficulties when large numbers of species are to be handled and described”. The correctness of this view is not immediately obvious. In the first place, it is hard to see why the same characters should be easier to handle as generic than as specific distinctions; fur- thermore, it should be borne in mind that the pursuit of science is not an armchair occupation. In compatison with large genera of other groups — the pennatulid genus Pferoéides, for instance, or the cirriped genus Galanus — or even with the hydroid genus Plumularia, the species with which we are here concerned are neither more numerous nor more difficult of distinction; yet it has not hitherto been found necessary to break up one genus into several merely because it comprised a large number of species, or because these were difficult to distinguish one from another; any such subdivision should be based upon grounds of far greater scientific importance. The “insurmountable” difficulties in connection with the Campanularide arise from the enormous number of badly described species which have been established — often, moreover, on the basis of inadequate investigations with regard to the study of variations. The result is a state of things which absolutely precludes a thorough biogeographical sur- vey. And this is just where the recognition of phylogeny as fundamentum divisionis would help us to clear matters up; from a biogeographical point of view, co-operation between phylogeny and biology is of the highest interest, and by giving phylogeny the precedence, with biology in the second place, we should obtain a sound basis and definite lines on which to set about a rational reconstruction of the chaos at present existing, particularly with regard to the Campanulariide. We have, as a matter of fact, to face the simple question, whether biology or phylogeny is to be regarded as the fundamental principle for systematics. The medusa system, in its present state, cannot help us in dealing with the thecaphore hydroids. The plasticity of the pelagic organism under the influence of -physical factors in its environment is 1 Nutting still writes “Campanularide”. HYDROIDA II I51 enormous, and makes itself felt among the medusz to the same degree as among other planktonic organisms. But the variation of single species under different conditions has been even less studied in the case of the medusz than in that of the polyp generation, and our ignorance as to these and similar phenomena has given rise to a medusa system in which phylogeny and _ biological con- vergency or divergency have been intermingled to a tangled confusion. A very fine proof of this is afforded by the fact that the Campanulinide have their medusz distributed throughout almost all the families of Leptomedusze, and yet we cannot, from this, proceed to split up the polyp family in question into a similar series of new families. The question as to a division into genera on the basis of gonophore types should be decided by a reference to the genus Hydractinia. Following this principle to its logical conclusion, with the Campanulariide, we should have to make generic distinction be- tween the male and the female of Zaomedea Hexwosa WHincks, where, as we know, the female gono- phores are heteromedusoid, the males styloid. But if this is out of the question, what gonophore type can we consider as being generically adequate? The heteromedusoids are in reality the only ones which differ in principle from all remaining types, which, since the discovery of the reduced crypto- medusoid in Grammaria abietina (M. Sars) form a finite series. — In Campanularia imtegra (Macgilli- vray) [Campanularia compressa Clark] we find, during one part of the breeding season free medusa, at another, sessile eumedusoids; there is thus no clearer limit between free meduse and sessile gono- phores in Campanularide than in several other families. The only type of gonophore which appears to be of any value must then be that of Gonothyrea, This is a highly interesting biological pheno- menon; phylogenetically speaking, it is a typical cryptomedusoid, (cf. Kithn 1913 p. 187) differing but little from the gonophores in Cladocoryne. Its systematic value really lies in the fact that in certain forms, it is thrust out from the natrower gonotheca without breaking loose. From a biological point of view, this is a most interesting phenomenon, and we cannot but call to mind the gonophores in certain Zwbularia species, where the larve are likewise developed in the sessile, medusa-like gono- phore; it shows how nature here, in another way, has arrived at the same result as in several of the Diphasia species, in protecting the larvee during their period of development. Such care of the young occurs, of course, elsewhere in the animal kingdom, but in all other cases, it is regarded as a biological phenomenon, which from a phylogenetic — and thus also from a systematic — point of view is of quite subordinate importance. It may also be worth while to glance at one of the most interesting genera, Orthopyxis L,. Agas- siz, which Nutting (1915 p. 63) again seeks to revive by the side of Clytia and Campanularia, all on the basis of the gonophores. In his generic diagnosis, Nutting refers to the Medusze of Ortho- pyxis as “without tentacles or manubrium”, and under the heading of Orthopyxis compressa (l.c. p. 66) he states that Torrey (1902) gives for this species an illustration of “a medusa with 4 tentacles just escaping from the gonangium”; under Orthopyxis everta, again (l.c. p. 68) he informs us that “the female, at least, contain meduse which eject their ova into an acrocyst without liberating the meduse”. Nutting has here given us a striking illustration of the value both of the genus itself and of the characters on which it is founded. The genus in question is really a connecting link, standing as it does with one foot, so to speak, in each of the other biological groups which we find represented in the family Campanularide. 152 HYDROIDA II Here, as elsewhere, when drawing the limits of a genus, we must seek to emancipate ourselves from the interesting biological features of the gonophores, and have recourse to Levinsen’s funda- mental point of view; the study of the nutritive polyps and the colonies themselves. We find then, that the family falls into two great groups, according to the diaphragm of the polyp, the arrangement being further accentuated by the two fundamentally different colony forma- tions, the stolonial and the sympodial. Levinsen (1893) believed to have discovered that the dia- phragma of the one group or genus — Campfaniularia — was a double formation, consisting of a cen- tral, thin membranous diaphragm, proceeding from a circular inner thickening of the wall, the boundary between the main cavity of the hydrotheca and the basal chamber. A thorough investiga- tion of the point has convinced me (1909 p. 183) that Levinsen’s conclusion must be due to his not having employed microtome sections; for microtome series reveal the fact that the “diaphragm” in the Campanularia group is produced by the high power of resistance against dissolvent influences which characterises the basal part of the supporting lamella, and that a true diaphragm, i.e. a chitin- ose, membranous bottom under the basal ectoderm, is altogether lacking. Nutting (1915 p. 9) has arrived at a different result. He supports his view upon an unpub- lished manuscript of his pupil, J. H. Paarmann, and on original preparations by the same hand. It is on Paarmaun’s original drawings also, that Nutting’s text figures 24—44 are based. These figures appear to have been sketched from optical sections, not from microtome series, and present altogether the impression of being not particularly reliable. Nor is this impression removed by the following passage quoted by Nutting from Paarmann’s manuscript: “The simple diaphragm can with diiffi- culty be seen in optical section of the hydrotheca, while the complex diaphragm is plainly distinguish- able without sectioning”. Now the fact is, that the thickening of the wall in Camfanularia is as a rule fairly easily visible, while the true diaphragm here, in such North-European species as I have been able to investigate, does not even show up in microtome section. — Paarmann has figured the “complex” diaphragm also in our European species Campanularia verticillata (Linné). He gives, as a matter of fact, two figures of this, and the two are not very much alike (Nutting 1915, figs. 38 and 43); I have not, however, succeeded in finding the membranous part of the diaphragm in Euro- pean specimens of the species. Paarmann’s drawing also reveals a peculiarity in Laomedea flexuosa Hincks (l.c. text figs. 9 and 26), the free margin of the diaphragm being here double, a phenomenon which is not discernible in Kithn’s illustration (reproduced in Nutting’s text fig. 47) and is similarly lacking in my preparations. Details of this sort are apt to cast some doubt upon the value of Paar- mann’s drawings. — We should note, however, that all the species in which Nutting, following Paarmann, finds a “simple” diaphragm, have sympodial colonies, while among species with “complex” diaphragm only two species are cited: Obelia geniculata (Linné) and Obelia flabellata Hincks, which have no stolonial colonies. From this is might be supposed that the two species should be regarded as types of a distinct genus, but this is not the case. Even in Paarmann’s drawing (Nutting 1015, text fig. 41) the diaphragm of Odelia flabellata is simple; somewhat thicker, it is true, than in most Laomedea species, but by no means resembling the broad wall thickening in Campanularia. ‘This, together with the sympodial growth of the colony, places the species undoubtedly in the Zaomedea group. With regard to Obelia geniculata, it might be a somewhat different matter. This species HYDROIDA II 153 evinces a remarkably high power of variability in the thickness of its chitinose parts, a point which has been noted by Semundsson (1902 p. 57) and later by myself (1909 p. 190); this variation, more- over, also affects the diaphragm in a peculiar manner. In finely built specimens, the diaphragm is of the same structure as in typical Laomedea species, that is to say, it consists merely of a thin basal plate spread out below the base of the polyp; in colonies of coarser build, the chitinose thickening makes itself especially apparent in the adthecal part of the diaphragm, only approaching the margin at a much later stage, so that in longitudinal hydrotheca sections, the diaphragm appears triangular, supported on a broad base-resting upon the hydrotheca wall. The diaphragm here, however, is in no wise more “complex” than before, and does not particularly resemble the low, ring-shaped wall thickening in Campanularia. Taking all this in connection with the sympodial development of the colonies, we can have no doubt we have here to deal with a typical Laomedea. The figure of Zaomedea flexuosa mentioned above as reproduced by Nutting after Ktthn (1909 Taf. 17, fig. 7) shows the typical Laomedea diaphragm. A typical picture of what we find in Campanularia is shown in fig. 1, Pl. 1. Gen. Campanularia (Lamarck). s . . . . - The colonies are stolonial, creeping or upright rhizocaulomes. The hydrothecee have no true diaphragm, but are divided by an inner thickening of the wall, more or less restricted in extent, into a large outer cavity and a smaller basal. The polyp can withdraw entirely into the radially symme- trical hydrotheca; it has a club-shaped proboscis and homogeneous gastrai endoderm. Quite exceptionally we find, among certain species, a slight approach to the formation of up- right colonies based upon a sympodial mode of ramification, so that one stalk may carry a single secondary lateral stalk with hydrotheca. This must be regarded as the earliest indication of the typi- cal sympodial colonies which characterise Zaomedea. The Campanularia species lack true diaphragm, but have a ring-shaped thickening of the wall (plate I fig. 1) which forms the upper limit of the basal cavity, and furnishes, in its superior part, the point of attachment for the basal supporting lamella of the polyp, which is fixed to the thickened part by a wreath of small chitinose bodies. The chitinose thickening may be broad and not very sharply defined, or more sharply defined and nar- rower, in which latter case it assumes the character of an incipient diaphragm, but also in this case it is restricted to a low ridge. Campanularia volubilis (Linné) Schweigger. 1758 Sertularta volubihs, Linné, Systema naturee, Ed. ro, p. 811. 1820 Campanularia volubilis, Schweigger, Handbuch der Naturgeschichte, p. 425. Creeping colonies, from the stolons of which proceed the hydrothece stalks, these being as a rule distinctly coiled in a spiral throughout their entire length; more rarely, the spiral may be less marked in certain parts, or throughout the entire length of the stalk. The stalk invariably termin- _ates in a distinct ball-shaped joint under the hydrotheca. The hydrothecze themselves are not very The Ingolf-Expedition. V. 7. 2c 154 HYDROIDA II large, about twice as long as broad; they are very nearly cylindrical, or somewhat tumid in the lower third, and with a very slightly expanded opening section; the basal third or fourth part of the hydrotheca tapers down, after an evenly curved transition part, rapidly to the stalk. The basal cavity of the hydrotheca is small, separated off from the main chamber by a narrow, but as a rule fairly prominent ring-shaped thickening of the inner wall. The transverse section of the hydrotheca at the aperture is circular, the opening margin has from nine to thirteen low, but generally di- stinct. rounded teeth. The gonothecz proceed from the stolons. They are oval to bottle-shaped, with a very short, often ringed stalk, in the broad end, and a long and narrow, cylindrical distal neck. Thegonotheca is smooth, often slightly asymmetrical, rarely with curved neck. Material : “Ingolf’ St. 33 67°57’ N., 55°30’ W., depth 35 fathoms, 0,8° — - 86 65°03,6’ N., 23°47,6°W, — 76 — -- — - 87 65°02,3' N., 23°56,2’ W., — 110 — a “Thor”, 65°52’ N., 23°58’ W., depth 62 metres. _ 64°16’ N., 22°17’ W., — 5 — — GARO2) NEN 622233 WE, — 34 — Greenland: Kutdlisat, Disco (depth not stated) Proven ( — - — ) flabeled Clytia Johnstonz] Store Hellefiskebanke, off Holstensborg, depth 18—2o0 fathoms Lille Hellefiskebanke (without further details) Sukkertoppen, on Goltenia (depth not stated) Frederikshaab ( — - — ) Iceland: Seydisfjord, depth 6 fathoms Vestmano, — 25 — Hvalfjord, — 22 — 3redebugt, 65°17,5' N., 23°22’ W., depth 7—12 fathoms — 64°45,8’ N., 23°55,2° W., depth 30 — Stykkisholm, — 20-30 — 6 miles W. of Iceland, (without further details) [some of them labelled Campanularia Sohnstont| Patreksfjord, depth 15—50 fathoms Off Dyrafjord, depth 30 fathoms. The Faroe Islands: 6 miles N. by W. of Store Kalsé6, depth 60 fathoms 7 miles N. by E. of Myggenzes point, depth 57 fathoms Deep hole at north point of Nols6, depth roo fathoms. Campanularia volubilis is a circumpolar boreal species, with a very wide distribution in the arctic areas; it would perhaps be more correct to describe it as an arctic-boreal species. It does not penetrate very far into the warmer waters, and the records as to its occurrence in the Mediterranean HYDROIDA II I on nn would seem to be exclusively due to confusion with Campanularia Johnstont Alder (ci. Broch 1912 p. 51). The species belongs chiefly to the littoral region, especially its upper half, but may quite excep- tionally penetrate some way down into the abyssal. Within the waters investigated, Campanularia volubilis is one of the most common Campanulariude; it is but rarely found, however, out in the open sea regions, which must probably be understood as standing in connection with its bathymetrical character (fig. LXXX). The species is not uncommon in West Greenland waters, but on the east 200 m. es See OEE Seen et NO OOTT: Bo eierdeah se COON: Fig. LXXX. The distribution of Campanularia volubzlis in the Northern Atlantic. In the hatched regions a common although scattered occurrence is stated. coast of Greenland it has only been met with north of 76°. Of the Iceland coasts, it seems to preter the east and west; it is less frequent at the Faroe Islands, and is stated as being of common, though scattered occurrence round the British Isles and off the west coast of Norway. Campanularia verticillata (Linné) Lamarck. 1758 Sertularia verticillata, Linné, Systema naturee, Ed. 10, p. 811. 1816 Campanularia verticillata, Lamarck, Histoire naturelle, vol. 2, p. 113. nec. 1907 Campanularia verticillata, Hickson and Gravely, National Antarctic Expedition, p. 23. Upright, stiffly built rhizocaulomes, from the numerous tubes of which the hydrotheca stalks proceed, arranged approximately in wreaths. The stalks exhibit distinct rings, which are most pronoun- ced near the origin, and nearer the hydrotheca; the stalk always terminates under the hydrotheca in a ball-shaped joint; the middle of the stalk is generally smooth. The hydrotheca is about twice as 20° 156 HYDROIDA II long as broad, cylindrical, with a curved basal part tapering sharply towards the stalk. The hydro- theca is circular in transverse section near the aperture; the opening margin is furnished with ten to fourteen low, rounded teeth. The basal cavity of the hydrotheca is small; the limit between this and the large main chamber is formed by a low, but often fairly narrow and sharply defined ring-shaped inner thickening of the wall. The gonothecze proceed from the tubes of the rhizocaulome, and are attached to the same by an almost rudimentary stalk. They are bottle-shaped, with a broadly rounded basal part, and a short, rather narrow, tubulous neck, as a rule curved or somewhat asymmetrical. Material: “Ingolf St. 127 66°33’ N., 20°05’ W., depth 44 fathoms, 5,6°. “Thor” 64°02’ N., 22°33’ W., depth 34 metres 63°30’ N., 20°14 W.. — 80 — Greenland: Davis Strait, depth 80 fathoms (without further details) — — , 67°24’ N., 55°39’ W. (depth not stated). Iceland: Vestman6, depth 49 fathonis. The Faroe Islands: 6 miles N. by W. of Store Kals6, depth 60 fathoms Glyversnees near Thorshavn, together with red alge (depth not stated). Campanularia verticillata is a circumpolar arctic-boreal species, penetrating only slightly to the south, but still met with off the coast of France. The statements in one or two recent works, how- 600m sastaasonee OOO ITI eee eae 2 OOO: 200 m. ee Fig. LXXXI. The distribution of Campanularia verticillata in the northern Atlantic. In the hatched regions the literature notes a common occurrence. HYDROIDA II 157 ever, (Kramp 1914 p. 1069; Nutting 1915 p. 31) as to its also belonging to the antarctic region, are incorrect. Hickson and Gravely (1907 p. 23) mention, it is true, Campanularia verticillata var. grandis from Mc Murdo Bay, but what they found there was, as Vanhéffen has pointed out (1909 p- 294) really the altogether different antarctic species Campanularia lobata Vanhoffen, which has but one character in common with our northern Campanularia verticillata: the fact that the colonies are, as in the latter, rhizocaulomes. Campanularia verticillata is thus not a bipolar species. — Campani- laria verticillata belongs to the middle parts of the littoral region, but may also be met with in quite shallow water; not infrequently also, it may penetrate down into the abyssal region, where it has even been found at no less than 600 metres’ depth. Its distribution in our seas (fig. LXXXI) shows that it is restricted to the coastal waters. The species is not uncommon on the west coast of Greenland; ou the east coast, however, it has only once been taken north of 76°. In Iceland waters, it seems to keep chiefly to the southern coast; it is also found scattered about the Faroe Islands. Round the British Isles and off the coast of. Norway it is of very common occurrence. Campanularia groenlandica Levinsen. 1893 Campanularia groenlandica, Levinsen, Meduser, Ctenophorer og Hydroider p. 26 pl. 5 figs. 1o—r2. Creeping colonies, from the stolons of which the hydrotheca stalks proceed; the latter may be ringed throughout their entire length, or, more commonly, having a smooth middle part; more rarely, the rings are found to be almost entirely lacking. The stalk invariably terminates under the hydro- theca in a ball-shaped joint. The large hydrothece are about 11/, times as long as broad, typically bell-shaped, with gently curving sides, the greatest bend occurring in the basal third to fourth of the hydrotheca. At the aperture, the hydrotheca is polygonal in transverse section, with from ten to fifteen, generally twelve or thirteen straight or slightly concave sides, each running out at the opening into a markedly prominent rounded tooth. In the intervals between the teeth, the margin is slightly curved outwards. The basal chamber is quite low, and bounded at the top by a faintly developed narrow ring-shaped inner thickening of the hydrotheca wall. The gonothecz proceed from the stolons, and are attached to the same by a rudimentary stalk. They are elongated oval or bottle-shaped, with a fairly long, narrowly cylindrical neck; they are smooth or indistinctly wrinkled, generally somewhat asymmetrical; the neck is straight or more or less curved. Material: “Ingolf St. 31 66°35’ N., 55°54’ W., depth 88 fathoms 1,6° ee eS LOS aU MeO mn SAM Amy ane 15508 i= = — =o O5sO230IN 2250.2, We — 110 — — Greenland: Davis Strait — 80 — (without further details)) | Levinsen’s Store Hellefiskebanke ( = — — )J type-specimens Iceland: 64°17,5' N., 14°44’ W., — 7GemMetes, 5,127 Bredebugt, 65°45,8’ N., 23°55,2’ W., depth 30 fathoms. 158 HYDROIDA II Campanularia groenlandica is a circumpolar arctic species belonging to the littoral region. It is undoubtedly of more common occurrence than the data to hand appear to show; this is probably owing to its having been confused with Campanilaria Hincksii Alder, the prismatic hydrothece of which present a certain likeness to those of Campanularia groenlandica. That such confusion has taken place as far as the Norwegian waters are concerned would seem to be beyond doubt; we find here, that Campanularia groenlandica moves southward at any rate as far as Trondhjem Fjord (fig. LX XXII). The species has once or twice been encountered off the east and west coasts of Iceland; on the east coast of Greenland it has not been met with south of 76°, but along the whole of the west coast, which is its classical ground, it is fairly common, occurring often in company with Campanularia volubilis. 200: re aa C00) mr) ee eae eee fooom, Tease IOI Fig. LXXXII. Finds of Campanularia groenlandica in the Northern Atlantic. Campanularia speciosa Clark. 1876 Campanularia speciosa, Clark, Report on the Hydroids.... Alaska, p. 214, pl. 9, fig. rz. 1913 Campanularia magnifica, Fraser, Hydroids from Vancouver Island and Nova Scotia, p. 164, pl. 11, figs. 1—3. Creeping colonies, from the stolons of which proceed shorter or longer, irregularly wrinkled or ringed stalks, terminating under the hydrotheca itself in a ball-shaped joint. The large hydrothecze are swollen at the bottom, with gently curving sides, narrowing upwards, but rapidly expanding again distally near the aperture, so that the opening margin curves strongly outwards. The margin is HYDROIDA II 159 furnished with seven to ten broad, slightly prominent teeth. The opening part curving more strongly out between the teeth, we have a broad furrow running from the highest point of the teeth and continuing some way down the hydrotheca, where it disappears. The longitudinal axis of the hydrothecz is often somewhat curved. The basal cavity is very small, bounded at the top by a sharply defined, fairly prominent ring-shaped thickening of the inner wall. The gonothece are attached to the stolons by a short, often rudimentary stalk. They are egg- shaped to oval, attached to the stalk by their broad end, and running out distally to a fairly long, narrow cylindrical neck. The gonothece are often slightly bent, and faintly and irregularly wrinkled transversely. Material: Greenland: Store Hellefiskebanke, depth 24 fathoms. The above-noted synonym Campanularia magnifica Fraser (1917 p. 164, pl. 11, figs. r—3) ought not really to require any further explanation. Fraser (1917 pl. 11, fig. 4) figures for purposes of com- parison a gonotheca of Camfanularia speciosa from Alaska; this is, like the one shown by Levin- sen (1893 pl. 5, fig. 7) a developmental stage, only a little younger still. I have previously described the fully developed gonotheca after specimens from the Kara Sea (1912 p. 18 fig. 3); the conformity with Fraser’s pl. 11 fig. 2 is evident. The other distinctive characters noted by Fraser are void of all significance, as will be seen from a somewhat richer material of the species. Campanularia speciosa is a panarctic species, belonging to the shallower parts of the littoral region. Within the areas investigated, it is only known from West Greenland, where its most south- erly occurrence was noted on the Store Hellefiskebanke. Campanularia integra Mac Gillivray. 1842 Campanularia integra, Mac Gillivray, Catalogue of the marine Zoophytes of the neighbourhood of Aberdeen, p. 465. 1853 — caliculata, Hincks, Further notes on British Zoophytes, p. 178, pl. 5, fig. B. 1876 _ compressa, Clark, Report on the Hydroids.... Alaska, p. 214, pl. 8, figs. 5—6. IQOI = Rittert, Nutting, Papers from the Harriman Alaska Expedition, p. 171, pl. 17, fig. 5. IQI5 — — Nutting, Campanularidae, p. 35, pl 2, fig. 2. IQI5 — miegra, Nutting, |. c. p. 33, pl. 1, fig. 7, pl. 2, fig. 3. 1915 Orthopyxts caliculata, Nutting, l.c. p. 64, pl. i5, fig. 4. I9I5 _- compressa, Nutting, l.c. p. 65, pl. 15, figs. 5—1rO0. Creeping colonies, from the stolons of which proceed hydrotheca stalks, smooth, or more or less distinctly ringed or spirally coiled, especially near their origin, and close under the hydrotheca; the stalk here always terminates in a ball-shaped joint. The hydrothece are large, inversely conical to nearly cylindrical; the conical ones taper gently down throughout their whole length towards the stalk; otherwise, the hydrothecz are rounded smoothly off at their basal part; every possible kind of intermediate form may be found. The hydrotheca margin is smooth, with no indication of teeth, 160 HYDROIDA II often curving slightly outward. The basal chamber is well developed, and bounded at the top by a more or less pronounced ring-shaped thickening of the wall, often with a fairly thick base. The gonothecee are attached to the stolons by a short, generally rudimentary stalk. They are oblong oval to cylindrical; the wall is often furnished with oblique furrows forming a spiral, but may as often as not be quite smooth; all intermediate forms and types occur in one and the same colony. The gonophores are eumedusoid and sessile, or break loose during a part of the breeding season as defective medusz (A4gastra). Material: “Ingolf St. 34, 65°17’ N., 54°17’ W.; depth 55 fathoms -- - 127, 66°33' N., 20°05’ W.; — 44 — 4,6° Sion 64°02' N., 22°33’ W.; — 34 metres Greenland: Godhavyn (depth not stated) Jakobshayn ( — = =) Egedesminde ( — - — ) Store Hellefiskebanke, off Holstensborg (depth not stated) Davis Strait, depth 100 fathoms (without further details) Sukkertoppen on algze (depth not stated) Godthaab ( — - — ) Iceland: Bakkefjord, depth 1o fathoms Vopnafjord, on littoral algee Seydisfjord, depth 6 fathoms Vestman6, on littoral alge Reykjavik, depth 2—3 fathoms 10 miles W. of Akranes, depth 26 fathoms Keflavik, on littoral alge Bredebugt, 65°17,5' N., 23°32’ W., depth 7—12 fathoms — 65228;5 Ny 23502) Wis — 9-12 — Stykkisholm — 30 — The Faroe Islands: Svin6d, on laminarians, depth 60 fathoms. The synonymy of this species should be clear enough after the investigations which have been made by Levinsen (1893) Kramp (1911) and myself (1909); nevertheless we find, that Nutting (1915) again distributes the species among no fewer than four, and even places these in two different genera. With regard to the transition stages between Campanularia integra and Orthopyxts caliculata, we find the following (1915 p. 34) “Broch... says that the gonangia of the two species intergrade, but I have seen no instance of the kind, and, as the two may occur together, a very careful. dissection would be necessary to place the matter beyond doubt”. It is precisely such careful dissections which have convinced Levinsen and myself that all transition forms and variants do occur on the same stolons; we have only to regret that Nutting has not been equally conscientious in his methods of work. HYDROIDA II 161 It might be supposed that Nutting’s material of Campanularia integra was restricted to some few colonies from scattered localities, each representing accidental variant groups, since the species is distributed under four separate names. The above indication of the methods pursued, how- ever, taken together with the following statement, will give a good idea as to the cause (Nutting IQI5 p. 34): “It should be understood moreover, that the present writer repudiates the idea that occas- ional intergradation in these low forms is sufficient ground for uniting species that are usually and perfectly distinguishable”. Giard (1899) has pointed out that the gonophores in Campanularia integra break away during MeO Wh eS DOO SS - fo09m, mato es GE Fig. LXXXIII. Distribution of Campanularia integra in the Northern Atlantic. In the hatched regions a common occurrence is stated. ‘ part of the breeding season as defective medusz, but are otherwise sessile. The correctness of this observation has been doubted, but is further confirmed through the investigations of Behner (1914). This writer refers to the species investigated as Campanularia compressa Clark, but it is impossible to discern wherein the difference between that species and Campanularia integra should be supposed to lie. The species thus stands with one foot in each of the two old genera Campanularia and Clytia. Nutting grasps at this as a welcome opportunity of separating off yet another genus, Or/ypyx7s, and believes to have rendered the system clearer and easier to deal with thereby. Campanularia integra 1s a purely cosmopolitan species, which prefers the upper part of the littoral region, but may nevertheless occassionally be met with a good way down in the abyssal, exhibiting thus, apart from its enormous power of variation, a high degree of elasticity with regard to temperature. In respect of salinity, on the other hand, it appears to be more susceptible, and does The Ingolf-Expedition. V. 7. 21 162 HYDROIDA IIL not move far up into the fjord waters. This may possibly also account for the distribution of the species within the area investigated (fig. LXXXIII). Campanularia integra is very common along the west coast of Greenland, but lacking on the east coast south of 76° N., according to what we know up to the present. The remarkable paucity of hydroids — arctic or boreal, — along this coast can- not be explained as due exclusively to temperature conditions, but must doubtless, judging from Cam- panularia integra, be partly occasioned by an accumulation of the fresh glacier water along the shore in contrast to the west coast, where warmer atlantic currents occasion a livelier interchange of water supply. A further peculiarity appears to lie in the scantiness of the species at the Faroe Islands; this, however, may possibly be accounted for by the fact that zoological bottom investigations have for the most part been made at greater depths than those at which the species chiefly lives in these waters. Campanularia Hincksii Alder. 1856 Campanularia Hincksit, Alder, A notice of some new genera and species, p. 360 pl. 13, fig. 9. Creeping colonies, from the stolons of which proceed long hydrotheca stalks, more or less distinctly ringed above their point of origin and under the hydrotheca; the stalk terminates below the hydrotheca in a ball-shaped joint. The hydrothece are very nearly cylindrical, with an evenly curving, rapid transition from the bottom to the stalk. In transverse section, the hydrotheca is poly- gonal, with eight to fourteen straight sides, each running out at the opening into a strong tooth, transversely cut off; the teeth may also at times exhibit a slight median incision. The basal cavity is small, bounded at the top by a sharply defined low and narrow ring-shaped thickening of the inner wall, The gonothecze are attached directly or by a rudimentary stalk to the stolons. They are elongated egg-shaped, broadest about the lower third, cut off transversely at the distal part, and with more or less prominent transverse furrows. Material: Iceland: Vestman6, depth 28 fathoms. North Sea: 57°07' N., 2°40’ E., depth 37 fathoms. Scemundsson (1911 p. 77) mentions under this species an instance im which an approach to rhizocaulome formation was found, giving rise to a stem 1 cm high, whereby the colony assumed a considerable resemblance to Campanularia verticillata. Campanularia Hincksii is a southern species doubtless more rare in northern waters than would appear from the records extant. It has frequently been confused with Campanularia groenlandica, which it somewhat resembles in a sterile state. Its occurrence in arctic waters is in reality very doubtful, and we must await further data before we can decide its biogeographical character with any certainty. HYDROIDA II 163 Campanularia Johnstoni Alder. 1856 Campanularia johnstont, Alder, A notice of some new genera and species, p. 359, pl. 13, fig. 8. 1860 Clytia bicophora, 1.. Agassiz, Contributions to the natural history of the United States, Second Monogr. vol. 4, p. 304, pl. 29, figs. 6—9. 1868 — johknstoni, Hincks, A History of the British Hydroid Zoophytes, p. 143, pl. 24, fig. 1. Creeping colonies, from the stolons of which proceed fairly long hydrotheca stalks, ringed at the base and below the hydrothecz, the middle part generally smooth. The stalk terminates below the hydrotheca in a ball-shaped joint. The hydrothecz are of varying size, from twice to 2"/, times as long as broad, cylindrical or inversely conical, with gently curving basal part. The hydrotheca is circular in section at the aperture; the opening margin is furnished with ten to sixteen sharp or point- edly rounded, highly prominent teeth. The basal cavity is rather large, terminating at the top in a narrow, sharply defined ring-shaped thickening of the inner wall, which in finely built specimens often presents the appearance of a very low diaphragm. The gonothece are attached to the stolons by a short, ringed stalk. They are cylindrical, narrowing sharply at the base, cut off transversely at the distal end, and have deep transverse furrows generally forming a slowly ascending, close spiral. The gonophores develope into free medusee (Clytia). Material: Iceland: Vestmané, depth 25 fathoms. The Faroe Islands: 6 miles N. by W. of Store Kalsé, depth 60 fathoms deep hole at north point of Nolso, — I00 — 61°40’ N., 7°40’ W., — 135 _ North Sea: 57 OF ING 1 2740 ter, — 37 — Nutting (1915 p. 54) endeavours once more to divide Campanularia Johnstoni from Clytia bicophora, partly on the ground that the latter species is said to possess a diaphragm, partly because it is finer in the chitinose parts. The thinner chitinose formations involve, in Campanularia Johnstont as in other species, a more restricted thickening of the wall, so that there may often be some con- siderable resemblance to a low diaphragm, and hydrothecze of this type always exhibit a marked ten- dency to wrinkle up on preservation. There is, however, no reason to take all this as furnishing sound specific characters, and we also find that all other investigators agree in uniting the two spe- cies as Campanularia Johnstont. This is doubtless correct. Campanularia Johnstoni is a widely distributed southern form, which thrives to a marked degree upon Sargassum; it can, however, penetrate quite far down within the littoral region. In the northern seas (fig. LXXXIV) it appears as a southern visitor, found once so far to the north as Hammerfest on the coast of Norway, but otherwise only once met with at Bergen. In the North Sea it is more common, as also at the Faroe Islands; it is of very frequent occurrence round the British Isles, but rare in Iceland waters, Its distribution is that of a species typically belonging to the warm atlan- tic current, 21° 164 HYDROIDA II restensacsscusvessomn@OOnIns Sooo oS OR tmp ere eee 1000 M, dc evssmnteenssane. 2000 M71. Fig. LXXXIV. The occurrence of Campanularia Johnstoni in the northern Atlantic. In the hatched region a common occurrence is stated. Gen. Laomedea Lamouroux. Upright, sympodial colonies only o¢casionally exhibiting creeping parts with unbranched polyp stalks. The hydrothecze have a typical broad diaphragm which forms the boundary between the main cavity and the basal chamber. The polyps can be withdrawn entirely into the radially symmetrical hydrothecee. The hydranth has a club-shaped proboscis, and homogeneous gastral endoderm. Lamouroux (1812) gave the following diagnosis of the genus: “Polypier phytoide, rameux; cellules stipitées ou substipitées, eparses sur les tiges et les rameaux”. This thus embraces the up- right colonies of Campanulariide, but Lamouroux has nevertheless placed Campanularia verticillata in his genus Ciytia. There is thus no reason to suppress the name Laomedea for later and more narrowly restricted genera, and we cannot, on phylogenetic grounds, break up the genus as here defined on account of the biological peculiarities apparent in the gonophores. Nor is a better survey obtained by dividing the genus according to the nature of the gonangia, which it is in most cases impossible to determine with certainty from the colonies obtained. And that characters should be easier to handle when raised to generic rank than when applied to species it is not easy to understand. In this genus, we find quite exceptionally that certain species, such as Laomedea dichotoma (Linné) may occur with creeping growth modification (ci Broch 1913 p. 55); in such case, however, the diaphragm distinctly shows to what genus the species must belong. These creeping parts are HYDROIDA II 165 biological adaptations, which cannot in themselves afford grounds for distinction of species. How they arise, however, has not yet been thoroughly explained. Laomedea fiexuosa Alder. 1850 Laomedea flexuosa Alder, Description of three new British Zoophytes p. 440. Upright, bushy colonies with monosiphonic hydrocaulus. There is no thickening of the peri- derm under the apophyses. Branches and stem are zigzag, with a short, ringed hydrotheca stalk from the apophyse at each bend. ‘The hydrotheca is as a rule 1'/, times as long as broad, or hardly as much. In shape it is inversely conical, with sides very slightly curved and quite smooth margin The basal cavity is large, bounded at the top by a distinct diaphragm. The hydrotheca exhibit no unilateral thickening of the wall. The gonothecz are carried on short ringed stalks proceeding from the apophyse beside the hydrotheca stalk. They are slenderly conical, as a rule tapering narrowly upward again at the distal part, and cut off broadly transversely at the distal end, without neck. The gonophores are dimorphous, the males styloid, the female heteromedusoid. Material: Iceland: Vestman6, on the beach Grindavik (depth not stated) Reykjavik ( — - —) Grafarvogur ( — = — j Laomedea flexuosa is a boreal species characteristic of the tidal zone. On a former occasion (1909 p. 228 footnote) I suggested that the recording of this species from deeper water, down to 60 metres depth near Iceland, must be due to confusion with other species. A revision of Semunds- son’s material has entirely confirmed the correctness of this; the specimens he mentions (1902 p. 56) from deeper water are Laomedea geniculata (Linné) and Laomedea longissima (Pallas). Semunds- son later (1913 p. 78, footnote) quotes in support Levinsen’s determinations from the cruises of the “Hauch” (1893); these, however, must be taken with some reserve, and they will probably only be found correct provided they refer to water layers of very low salinity. In fjords with an inter- mixture of fresh water and in inland seas, the limits for the tidal zone will require to be somewhat modified, if it is to correspond with the conditions for fauna and flora in the tidal zone of the open sea shore. The deepest-living Laomedea flexuosa are met with out here on the upper Laminaria, which at deepest low water are not infrequently’ found lying dry; up in the fjords also the upper Lamznaria must be taken as the limit, though they are here only found considerably deeper. Here, however, Laomedea flexuosa rarely goes so far down. The species is, as mentioned, boreal,-characterising the tidal zone along the coast of Scandinavia, round the British Isles and at Iceland; it will probably, on further investigation, also prove to be common at the Faroe Islands, In Greenland waters, however, the species seems to be altogether lacking. It does not penetrate into the strictly arctic tracts. 166 HYDROIDA II Laomedea geniculata (Linné) amouroux. 1758 Sertularia geniculata, Linné, Systema naturee, Ed. 10, p. 812. 1816 Laomedea geniculata, Lamouroux, Histoire des Polypiers coralligenes flexibles, p. 208. 1864 Obelia gentculata, Allman, On the construction and limitation of Genera, p. 372. Upright, more rarely branched colonies with zigzag stem, the colony as a rule strongly built, and with an (inner) thickening of the perisare under the apophyse; the stem and branches without rings. The hydrothecze are borne on short, ringed stalks proceeding from the apophyses. Hydrothecze long, about as long as broad, inversely conical with slightly curved sides. The abcauline side has as a rule a thicker wall than the adcauline. The basal cavity is large, bounded at the top by a strong diaphragm, which, especially in colonies with strongly developed periderm, has a thickened adthecal part. The hydrotheca margin is even, without indication of teeth or convexities. The gonothecze are set on short ringed stalks proceeding from the apophyses at the side of the hydrotheca stalks. The gonothecze are slender, inversely conical, with a clearly defined, sharply tapering distal part, and short, narrow central neck. The gonophores develope into free medusz Obelia). Material: “Thor” 64°16’ N., 22°17’ W., depth 50 metres. -— 64°02) N., 22°33, W. = 34 — Iceland: Bakkefjord, depth 25—32 fathoms Seydisfjord, — 6 — Vestmand6, — 25 — [labelled Laomedea flexuosa} Reykjavik, — 3-4 — Olafsvik (depth not stated) [labelled Laomedea flexuosa| Stykkisholm, depth 6—9 fathoms sredebugt, 65°17,5' N., 23°22’ W., depth 7—12 fathoms — 65°18' N., 23°02’ W, — 9g—10 — Dyrafjord, on Lamznaria (depth not stated) Onundarfjord, depth 1o fathoms Adelvik, — 5-55 — Ofjord, on Lernea (depth not stated) Grimso, depth 15 fathoms Vidarvig, — 13,5 — Thistil fjord, Raudarnes 1.5 miles in $.51E., depth 18 fathoms. Jan Mayen, on Laminaria, depth 15 fathoms (Kast Greenland Expedition). The Faroe Islands: Thorshavn, depth 3—15 fathoms Vestmanhayn, — _ 10 — Solmunde, on Laminaria (depth not stated) Svin6, depth 20 fathoms, HYDROIDA II 167 Laomedea geniculata is a cosmopolite, belonging to the upper part of the littoral region; in northern seas it is chiefly restricted to the Laminaria, but may also occur on deeper-growing Zostera and on shallow red alge in large quantities. Albeit properly cosmopolitan, the species is nevertheless very rare in strictly arctic waters, but may occur here right into the White Sea. It is most frequent in the boreal areas. Along the coasts of Norway, round the British Isles, the Faroe Islands and Ice- land it is present in great numbers (fig. LXXXV). It is also mentioned from Greenland, but no de- finite locality has yet been recorded. Cee ih SS 600m. meme memes - 1000m. seme meee, 2000 M. Fig. LXXXV. The distribution of Zaomedea geniculata in the Northern Atlantic. In the hatched regions the species is abundant. Laomedea longissima (Pallas) Alder. 1766 Sertularia longissima, Pallas, Elenchus zoophytorum, p. 110. 1858 Laomedea _- , Alder, A Catalogue of the Zoophytes of Northumberland, p. 121. 1868 Odelia — , Hincks, A History of the British Hydroid Zoophytes, p. 154, pl. 27. 1868 — flabellata, Hincks, l.c. p. 157, pl. 29. Large graceful colonies with monosiphonic, brown stem, generally flexuous. From this pro- ceed secondarily ramified branches, which again give off a hydrotheca stalk from the apophyse at each bend, There is no thickening of the periderm under the apophyses. The hydrothece are about twice as long as broad, slender, inversely conical, with more strongly curved basal part. The hydro- theca margin is more or less curved, at times with distinct teeth, at others quite smooth. The basal chamber is fairly large, and bounded at the top by a finely built but distinct diaphragm. 168 HYDROIDA I The gonothecee are borne on short, ringed stalks, proceeding from the apophyses beside the hydro- theca stalks. They are oblong, inversely conical, distally cut off transversely with a central short and narrow, almost tubulous neck. ‘The gonophores develope into free medusze (Odea). Material: “Thor” 64°02’ N., 22°33’ W., depth 34 metres [labelled Laomedeca gelatinosa) _ 63°30’ N., 20°14’ W., — 80 — _- sor N. . 2°28) W. —— Gory = Greenland: Jakebshayvn (depth not stated) Provens havn ( — - — ) Holstensborge (— - — ) Tasiusak, depth 3—5 fathoms (Kast Greenland Expedition). Iceland: Berufjord, depth 6 fathoms [labelled Laomedea flexuosa] Hornafjord (depth not stated) [labelled ZLaomedea Lovenit| Vestmano, depth 25—28 fathoms [some of the specimens labelled Laomedea flexuosa] 10 miles W. of Akranes, depth 26 fathoms [labelled Laomedea flexuosa}. Stykkisholm, depth 20—30 fathoms |labelled Laomedea flexuosa| Kollafjord, 4—5 Dyrafjord (depth not stated). The Faroe Islands: 5 miles N. by E. of Myggenes point, depth 50 fathoms. tocee cw ecen cee cees 200 mM. eelesloviiesh oo ialast OO ONT sme e. 1000M, a ercearn CHR IIILE Fig. Y.XXXVI. The distribution of Laomedea longissima in the Northern Atlantic. In the hatched regions a common occurrence is stated. HYDROIDA II 169 Sterile colonies of this species with almost or entirely smooth margin may at times present a certain resemblance to ZLaomedea flexuosa, and have ‘frequently been confused with this species by Semundsson. — Nutting (1915 p. 73) endeavours to revive Obelia flabellata Hincks on the ground that the extreme branches of this species exhibit dichotomous ramification, whereas in the present species they are “flabellate”; unfortunately, however, he does not further explain the difference between the two terms. In the present colonies, both might often apparently be applied to the same branch. Nor does his other distinctive character, the fact that the branches in Odelia longissima are “regularly alternate” while those in Odetia flabellata are “alternate or opposite” give us any sound basis to work on. Bonnevie (1899 p. 71) is undoubtedly right in uniting the two species, and they cannot be revived on the strength of what Nutting here seeks to show. Laomedea longissima appears to be a cosmopolitan species, albeit the data on record from tropic-subtropical waters are but scanty. The species belongs to the upper third of the littoral region, and goes far up into arctic waters, where it has a circumpolar distribution. In the area investigated (fig. LXXXVI) it appears to be entirely lacking in East Greenland waters, but is otherwise fairly re- gularly met with on all coasts. Laomedea hyalina (Hincks) Levinsen. 1866 Gonothyrea hyalina, Hincks, On new British Hydroida, p. 297. 1893 Laomedea — Levinsen, Meduser, Ctenophorer og Hydroider, p. 28. Finely built upright colonies with monosiphonic main stem, the latter being, like the main branches, generally brown in colour. The colony often assumes a bushy appearance, owing to irre- gular ramification. The hydrothece are carried on short ringed stalks proceeding from the branch apophyses; the latter are set in a plane on the branch directed alternately to either side. The hydro- thecze are slender, inversely conical to cylindrical, tapering somewhat more at the basal part toward where the stalk begins; they are twice to three times as long as broad. The hydrotheca margin is furnished with low teeth, having a slight, often almost imperceptible median sinus in their distal end, which is cut off almost straight, so that they are divided into two denticles; from this sinus a slight furrow runs for a varying distance down the hydrotheca on its outer side. The basal chamber is small, bounded at the top by a thin, but well developed diaphragm. The gonothecze are borne on short, ringed stalks, proceeding from the apophyses beside the hydrotheca stalks. They are inversely conical, cut off straight at the distal end, without neck. The gonophores develope into crypto-medusoid meconidia, which extend out from the gonotheca without breaking away; the larval.development takes place in the interior of the meconidium. (Gonothyrea medusee). Material: “Ingolf” St. 34, 65°17’ N., 54°17’ W., depth 55 fathoms. Malet 66°23’-N., 14°24’ W., — 45 metres = OGG 2eNE ee E5S. Aes — 62 — [labelled Laomedea Lovent| — 64°16'_N., 22°17’ W, — 50 — ny iS The Ingolf-Expedition. V. 7. HYDROIDA II “Thor” 64°02’ N., 22°33’ W., depth 34 metres — 63°2010N,,. 20114" Wi, — 80 — |labelled Laomedea Lovent | Greenland: Proven (depth not stated) Umanak (0 =e Lees 5h) Christianshaab ( — - —_ ) [labelled Gonothyrea Lovent| Egedesminde ( — - — _) |labelled Gonothyrwa Loveni and Obelia longissima| Store Hellefiskebanke, depth 32 fathoms Sukkertoppen, on Pso/us and Boltenia (depth not stated) = (depth not stated) [labelled Odelia longissima). Iceland: Hvalfjord, depth 22 fathoms. labelled Gonothyrea Lovent | The Faroe Islands: without further details 6 miles N. by W. of Store Kalso, depth 60 fathoms Deep hole at north point of Nolso, — 100 — Laomedca hyalina is very closely allied to the Laomedea Lovent Allman, so much so that the two species have very often been confused. The characteristic distinctive marks of Laomedea hyalina are the fine narrow furrows running from the teeth some way down over the side of the hydrotheca, often giving the teeth themselves a double point. Nutting (1901 p. 352) mentioned intermediate forms between the two species from Plymouth; as however, the furrows in question are not noted by Nutting in the American waters, it is doubtful which of the species he has here been investigating. Probably all his specimens were typical Laomedea Lovent, Laomedea hyalina must, from the data on record, be characterised as an arctic boreal, atlantic species. Its true home appears to lie at the transition between boreal and truly arctic regions, and from there it extends both north and south, everywhere within the upper third of the littoral region. Kramp (1914 p. 1071) notes the species as circumpolar, citing in evidence Clark (1876 p. 215) who mentions a Gonothyrea hyalina from Alaska. Marktanner-Turneretscher however, (1895 p. 408) has pointed out that Clark’s specimens represent the type of a distinct species, Laomedea Clarki (Marktanner-Turneretscher). The validity of the species may seem somewhat doubtful, and it is highly probable that Kramp is correct in his geographical characterisation, but new and conscientious in- vestigations in American waters will be needed before we can be fully certain. Laomedea hyalina is widely distributed within the waters investigated (fig. LXXXVIJ). It is surprising to find that a species having so wide a distribution in the arctic regions appears to be altogether lacking 1 East Greenland waters; it is otherwise of general occurrence within the area concerned, but becomes less frequent around the British Isles and off the southern west coast of Norway. Laomedea gracilis M. Sars. 1851 Laomedea gracilis, M. Sars, Beretning om en i Sommeren 1849 foretagen zoologisk Rejse, p. 138. 1868 Gonothyrea gracilis, Hincks, A History of the British Hydroid Zoophytes, p. 183, pl. 36, fig. 1. Upright colonies, slightly and irregularly branched, finely and stiffly built. There are no distinctly prominent apophyses, but the branches and hydrotheca stalks proceed from a faintly marked HYDROIDA II 171 \ \ 2 BS ye at . aes ce Tied SN One Y Aone INES 200 mM. 5S oso 600m. Pp pero UOC Mab eee a ee OOOTI Fig. LXXXVII. The distribution of Zaomedea hyalina in the Northern Atlantic. In the hatched region the literature notes a scattered occurrence. 200 m. aesoe co SUGIC im oSocustices fooom. —.—..2000m Fig. LXXXVIII. The distribution of Zaomedea gracilis in the Northern Atlantic. In the hatched regions the literature notes a scattered occurrence. ) is} 172 HYDROIDA II monosiphonic main stem, which not infrequently appears to be dichotomously branched. The bran- ches and the hydrotheca stalks are ringed close above their origin, and below the hydrothecze, other- wise smooth. The hydrothecz are twice to three times as long as broad, cylindrical, or rather inversely conical, passing over by an evenly curved transition into a short, almost cylindrical basal part; the basal chamber is small, bounded at the top by a fine, well developed diaphragm, often somewhat assvmetrically placed. The hydrotheca margin is provided with seven to fourteen markedly prominent pointed or pointedly rounded teeth. The gonothecee are attached by short, ringed stalks proceeding from stem or branches, rarely from the stolons. They are inversely conical or slightly oval, elongated, cut off transversely at the distal end, without neck. ‘The gonophores develope into cryptomedusoid meconidia, projecting from the gonotheca without breaking away. The larval development takes place within the interior of the meconidium (Govzothyrea meduse). Material: “Thor” 64°02' N., 22°33’ W., depth 34 metres Iceland: (without further details) on the back of a Dinematura ferox taken from a Sommntosus mucrocephalus. Laomedea gracilis is a southern visitor to the northern waters (fig. LXXXVIII) where it pene- trates up to the northern point of Norway. The species is altogether of rare occurrence here, but has been taken more especially about the British Isles. One or two finds show that it also occurs sparsely at the Faroe Islands and south-west Iceland, always in the middle or upper third of the littoral region. Gen. Bonneviella (Broch). Stolonial colonies with enormous, often slightly, bilateral hydrothecee, having a finely built diaphragm. The large polyps can be withdrawn entirely into the hydrotheca. The hydranth has a crown of strong tentacles with multiserial endoderm; the oral part is thin, forming a thin lamella, consisting of two cell-layers, which a little above the tentacle base extend out like a velum in towards the central oral aperture. The tentacle base thrusts itself into the polyp, so that a large proboscoidal cavity is formed between this and the oral aperture. The gastral endoderm is uniformly developed. As already mentioned, I am unable to agree with Nutting, who is inclined (1915 p. 94) to support the view advanced by me in a former work (1909 p. 197), that the ectoderm covers the ten- tacle base and the inner side of the velum-like proboscoidal part. Kitihn (1913 p. 253) 1s justified in doubting whether the part in question can be reckoned as belonging to the endoderm, and I am more disposed to follow him here, considering the part as an extreme development of the indifferent endoderm cell-layer, as found for instance on the proboscis of Campanularude. The point can, how- ever, only be decided by study of the polyp development. The systematic position of the genus is still altogether doubtful. HYDROIDA II 173 Bonneviella grandis (Allman) Broch. 1876 Campanularia grandis, Allman, Diagnoses of new Genera and Species, p. 259, pl. 12, figs. 2—3. 1899 Lafoea gigantea, Bonnevie, Den norske Nordhavs-Expedition, p. 68, pl. 6, fig. 2. 1909 Lonneviella grandis, Broch, Hydroidenuntersuchungen, II, p. 198. The colonies form enormous upright and irregularly branched rhizocaulomes. From the tubes proceed hydrotheca stalks of differing length, often segmented, with a spherical swelling immediately below the hydrotheca. The latter are twice to three times as long as broad, swollen for the lower third part, somewhat narrower above, with expanded margin; in transverse section, the hydrotheca is circular below, oval nearer the aperture; the aperture itself is as a rule somewhat asymmetrical, the margin quite smooth. The basal cavity is small, bounded at the top by a quite thin diaphragm. The gonothecze proceed from the tubes of the stem; they are more or less closely set, and occur scattered about all over the colony. The gonothece are egg-shaped to spindle-shaped with six to eight longitudinal ribs and a short, narrow trumpet-shaped neck. Material: Iceland: 64°17,5' N.. 14°44’ W., depth 75 meters 5°12 The Faroe Islands: Thorshayn (depth not stated). The genus Zonneviella includes several species from the northern Pacific, for the further de- scription of which we are indebted to Nutting (1915 p. 95). One of these species is Lonneviella ». 200 mM. Se ost as OOM 1—---=—-—.- 1000M. eee cee OOD ETI Fig. LXXXIX. Localities of Bonneviella grandis in the Northern Atlantic. 174 HYDROIDA II grandis, first described from some colonies from Japan, Tsugor Strait, preserved at Copenhagen. The species differs from the others by its longitudinally ribbed gonothecee; the other species in which the gonangia are known, have the gonothece transversely furrowed. The next find of Bonneviella grandis was made off the west coast of Norway. We have since learned, that the species, besides occurring at several places in the North Pacific, is also widely distributed in European waters. It has been met with in the Barents Sea, at Lofoten (fig. LXXXIX), at Moldoen near Stat on the west coast of Norway. It is mentioned from the south-east point of Iceland and from Fyllas Banke in Davis Strait. We may now add some new localities; the Faroe Islands, and outside Isafjord, Iceland, where it was taken by the “Michael Sars” in the summer of 1903. Bonneviella grandis must thus be characterised as a boreal circumterrestrial species, belonging to the lower parts of the littoral region and the upper portion of the abyssal. III. Addenda to the Athecate Hydroida. In going through the athecate hydroids, some few glasses were overlooked, and are here included. Corymorpha nutans M. Sars (Part I, p. 31). Iceland: Keflavik (depth not stated) Bredebugt 65°12,5’ N., 23°28’ W., depth 36 fathoms. Corymorpha groenlandica (Allman) Broch (Part I, p. 33). “Ingolf? St. 15 66°18’ N., 25°59’ W., depth 330 fathoms + 0,75° This find forms an interesting complement to the former data (cf. Part I, text fig. I); it lies in Danmark Strait, on the northern slope of the threshold, and shows that the species also occurs be- tween Iceland and Greenland. Family Branchiocerianthide. Athecate hydroids without calcareous skeleton. The tentacles of the grown polyp, which are all filiform, make two main circles; the tentacles have a central cavity,not connected with the gastral chamber. The supporting lamella exhibits no particular development in any of the tentacles. The hydranths are bilateral in structure. At the base of the proximal tentacles, numerous radial canals occur, reducing the mesogloeal formations to a minimum. The gastral chamber is divided by a hori- zontal septum into two parts, a smaller proboscoidal, and a larger basal. The gastral endoderm is homogeneous in both. Gen. Branchiocerianthus Mark. The polyps are bilaterally symmetrical, the stalk being excentrically attached; the oral aperture also is excentrically situated, being thrust over towards the opposite side of the point where the stalk HYDROIDA II 175 is attached. The hydranth has a proximal tentacle crown, the growth of which takes place from the part of the hydranth periphery nearest the stalk, where the shortest tentacles are found. The tentacles of the oral circle are homogeneously developed. The periderm of the stalk is reduced and soft. The blastostyles are situate between the tentacle crowns, the youngest ventrally above the point of at- tachment of the stalk, The polyps are solitary. Allman (1888 p. 5) described the first Bvanchiocerianthus species, which was brought home by the “Challenger”, under the name of Monocaulus imperator, The family Monocaulide had been previously founded by All mann (1871 p. 395) with the following diagnosis: “Hydrocaulus solitary, naked. Hydranths with a proximal and a distal set of filiform tentacles. — Gonophores in the form of fixed sporosacs”. This diagnosis thus makes no mention of the essential point, to wit, the bilateral character of the polyp. Nor is any reference to this found under the heading of the only genus, AZomocau- Jus, which is thus described: ; “Hydranth abruptly distinct from the hydrocaulus; proximal tentacles longer than the distal and disposed in a single verticil near the base of the hydranth, the distal set scattered over a zone close to the summit of the hydranth. — Sporosacs borne upon peduncles, which spring from the body of the hydranth between the proximal and distal sets of tentacles. The genus A/fonocaulus is constituted for the Corymorpha glacialis of Sars, a form which, though its trophosome is that of a Corymorpha, is yet strongly distinguished from the true Corymor- phas by its adelocodonic gonophores” (Allman 1871, p. 396). In addition to Corymorpha glacialis, Allman also places Corymorpha pendula 1, Agassiz in the genus, this being a species with free medusee, Later on, Corymorpha groenlandica is also placed in the same genus. And here, finally, A/onocaulus imperator is likewise included, Allman (1888 p. 5) having entirely overlooked the bilateral structure of the species, and disregarding the morphological peculiarities noted in his descriptions. With reference to Corymorfha I have pointed out that Allman’s typical AZonocaulus, Cory- morpha glacialis M. Sars must remain in the genus where M. Sars placed it, like A/onocaulus groen- landica Allman, the only species which entirely answers to the diagnosis given by Allman. It would therefore be altogether wrong to follow the suggestion given in “Nomina conservanda” (cf. p. 53) and retain the generic name MMonocaulus for a genus where Monocaulus imperator has been somewhat arbitrarily chosen as type, the more so since the essential feature of the species, which is even cha- racteristic of the genus as a family type, was distinctly emphasised by E. L. Mark in 1899 in his description of the central American Pacific species Branchiocerianthus urceolus Mark. Since then, the genus has been referred to in all leading works under the generic name given it by Mark, Bran- chiocertanthus, and as the species in question have been accorded only the briefest mention in the handbooks, there will be no confusion caused by general adoption of the appellation. Moreover, after the publication of the fundamental studies on Branchiocerianthus by Mark (1899), Miyajima (1900), and Stechow (1908, 1909) it would certainly be confusing to adopt the name MJonocaulus. The genus Branchiocerianthus was hitherto only known from the Pacific (Alaska, Japan, Pa- nama) and the Indian Ocean (Beluchistan, Oman, and East Africa). Stechow, in his description of 176 HYDROIDA I Branchiocerianthus tmperator (1909, p. 71) states: “Da im tibrigen die Familie! ganz kosmopolitisch ist so diirfen wir woh] annehmen, dass Branchiocerianthus-Arten auch im Atlantischen Ozean vorkommen, bisher aber nur wegen ihres Lebens in groésserer Tiefe noch nicht gefunden worden sind”. Excellent proof as to the correctness of this supposition has now been furnished by the finding of a Branchiocertanthus in the deep part of Davis Strait, where it occurs together with other repre- sentatives of a southerly deep-sea fauna. Stechow’s characterisation of the habitat of the genus as “Kaltwassergebiet” however, is biogeographically erroneous; ASranchiocerianthus has not yet been met with in the cold area, and is hardly likely to prove a characteristic element in the fauna of that region. The genus belongs to the abyssal region of the warmer seas, or strictly speaking, that portion of the same which makes the home of the “intermediate fauna”. The temperature here may certainly fall ° retty low in certain places, but is never below o°% The “Kaltwassergebiet” would include the cold pretty p g area, where the temperature is constantly below 0°. Branchiocerianthus reniformis un. sp. (Pl._I, figs. 2—5). The hydranth, viewed from below, has a distinctly kidney-shaped appearance, with a deep (ventral) sinus reaching right in to the stalk. Owing to the depth of this incision, the stalk appears comparatively centrally situated, the distance to the dorsal edge (6 mm) being slightly more than that between the stalk and the margin of the disc perpendicular to the dorso-ventral axis (4,5 mm). The oral aperture seems to be somewhat more excentrically placed, being distant between a fourth and a third of the diameter of the disc from the dorsal margin of the disc. The oral aperture is very large, and in the present specimen it 1s curved over, revealing the highly folded gastral endo- derm (PI. I, fig. 3). It would almost seem as if the margin of the oral aperture were divided into lobes; from the single specimen here available, however, it is impossible to decide with certainty, whether this is natural, or due to accidental damage. The margin of the oral aperture is curled, with a closely packed tentacle crown, showing indications of multiserial arrangement. The oral tentacles are everywhere round in transverse section, and are strongly built. The basal tentacles form a single circle; they are very long, with exception of the ventral ones, which are placed along the margin of the disc in the incision. In the incision itself, the tentacles decrease rapidly in length in towards the stalk, at its base are the youngest tentacles, which are quite small. The basal tentacles are later- ally compressed at the base, where they easily fall off; in the present specimen, only the tentacles in the incision and a pair beside it are intact, the remaining ones having fallen away. The stalk of the polyp is thin, longitudinally striped. The short basal part is covered with numerous fine root hairs extremely closely set, forming a tangled mass round the end of the stalk and entirely covering it there. There is no zone of incipient root hair formation discernible above the developed part. The blastostyles form a crown, interrupted ventrally, about the hydranth between the tentacle crowns, nearer the basal. The blastostyles are closely set in a crown which may be up to triple- rowed. The large blastostyles divide near the base at once into two or three main branches of equal size, which later (Pl. I, fig. 5) again divide dichotomously at intervals two or three times. The top of tT. e. Corymorpha and Branchiocerianthus. HYDROIDA II 17 the blastostyle is shaped rather like a cluster of grapes, the outermost swellings, shown in the figure, consist each of a compact accumulation of incipient gonophores. Nematocyst-bearing terminal buds appear to be altogether lacking. The size of the blastostyles decreases nearest the ventral interval, whence a new formation evidently takes place. With regard to the anatomical character of the polyp, we must notice the large mesentery which divides the gastral cavity into an upper (oral) and a lower (basal) section; it has a large median opening. The radial canals have a large lumen; they do not appear to divide, and alternate with the tentacles, and thus do not stand in open connection with the latter; their number corresponds to that of the proximal tentacles. — The blastostyles are hollow, and communicate openly with the interior of the polyp, but it was impossible to determine exactly whether their communication with the gastral cavity is direct, or proceeding indirectly through the radial channel. Material: “Ingolf St. 28 65°14’ N., 55°42’ W., depth 420 fathoms, 3,2°. The only specimen procured presents the foliowing features: Total length 120 mm., of which 110mm. fall to the hydrocaulus. Distal diameter of the stalk 3 mm., close above the root hairs the transverse section is 7 mm. The polyp disc has a total breadth of 12 mm. and a length of g mm., measured from the bottom of the ventral incision. There are 85 proximal tentacles; the longest of those intact is 55 mm. The distal tentacles are very closely set, often displaced, giving a slight indication of three rows; there are between 80 and go oral tentacles of up to 5 mm. length. The blastostyles are closely packed together, and form three indistinct rows, the longest is 4 mm.; there are between 70 and 8o in all. On comparing the present specimen with the species of Branchiocerianthus previously described, we find several points of difference, albeit none very striking in itself. The peculiar kidney-shaped appearance of the disc (Pl. I, figs. 2 and 3), as also the curled margin of the oral aperture, would seem to be different from the species previously described, and has led me to regard the specimen for the present as representing a distinct species, Branchiocerianthus reniformis. The lack of terminal buds bearing nematocysts in the blastostyles brings the species near to Branchiocertanthus n. sp. Stechow, (1913 p. 54) from which, however, it is immediately distinguished by its undivided radial canals. The habitus of the hydranth distinguishes it from Branchiocertanthus urceolus Mark; this may, however, possibly be taken as due to a difference in the state of contraction. From Avranchiocertanthus impe- rator (Allman) again, the species differs in the lack of nettle buds on the blastostyles. From the appe- arance of the specimen in 1904, Branchiocerianthus reniformis has also a different colour; the body of the polyp was then white, the blastostyles being a deep violet blue; now, after having lain many years in alcohol, it is an even grey. The individual can hardly be fully grown, and corresponds in point of size only with the smaller specimens of Branchiocerianthus urceolus found. The number of proximal tentacles agrees mainly with that in this species, but there are far fewer distal tentacles; save for one of Allman’s specimens of Branchiocerianthus imperator (1888) all the other individuals found belonging to this genus had considerably more distal tentacles. The number of blastostyles takes up an intermediate place between the two mentioned species, and is somewhat lower than in Branchiocerianthus n. sp. The Ingolf-Expedition. V. 7. 23 178. HYDROIDA II Stechow (1913). As, however, the specimen is unique, and moreover, apparently not fully grown, these points should not be considered as of too great importance in the present state of our know- ledge. For the present, it will be most correct to regard the specimen as representative of a distinct species, bearing in mind, however, that subsequent investigations may possibly show it to be identical with one of those formerly described. Branchiocerianthus reniformts will probably, as the find suggests, prove to belong to the abyssal region. Its occurrence shows that the genus is of circumterrestrial distribution. IV. Zoogeographical observations on the Hydroid Fauna of the North Atlantic. The study of the bathymetrical distribution among hydroids still leaves much to be desired; the data on record are still somewhat scanty, and merely suffice to give an occasional glimpse of the regularity which will doubtless be found to prevail throughout this animal group, just as in others. It has been a generally accepted notion, and is so to some extent even now, that a marine animal species with a wide horizontal distribution will prove of shallower occurrence the farther north it is found in our waters, or rather, the farther it penetrates into the cold areas. This rule, however, is not universally applicable. True, we find that species which must be regarded as more or less arctic are met with in more southerly tracts in the deeper water-layers, but on the other hand, warm atlantic character forms which are found farther south up in the littoral region often exhibit, in the few northern finds made, a tendency to prefer even much greater depths. Evidently then, the biophysical conditions here approach more nearly to those prevailing in the southern home of the species, though we cannot at present find any further explanation of this. At any rate, the question is seen to be a good deal more complicated than was at first supposed, and the available data are unfortunately far from sufficing to give a thorough exposition of the biogeography in hydroids in the northern waters. In this connection, it will not be out of place to explain one or two expressious which are constantly recurring when dealing with the different species. I refer to the terms littoral and abyssal region. I have followed the general international acceptance in using “littoral region” for the upper 3—400 metres of the sea floor, “abyssal region” for depths beyond. It is true that certain northern writers have sought to give the terms in question new and sometimes quite different meanings. This, however, gives rise to confusion, and further complicates the still somewhat new field of research known as biogeography. The terms used should be as nearly as possible invariable, and should not require to be defined anew by each writer, as has hitherto been the case. Indeed, it might almost seem well to discard altogether the term littoral region, since it appears to be interpreted in almost as many different senses as there are writers in Scandinavia. I have here, however, as indicated, employed the expression in the general sense in which it is used outside the works of the scientists referred to. HYDROIDA II 179 A great majority of the northern hydroids are decidedly inhabitants of the littoral region, and among these we find a number of species which characterise its upper part, the tidal zone. This zone comprises, on open sea coasts, the belt between high- and low-water marks; in fjord grounds, how- ever, where the water is mixed with fresh, we are obliged, on account of the altered hydrographical conditions, to draw the lower limit somewhat farther down, where the laminarie begin. The tidal zone is in all parts of the northern waters characterised by Fucoids, and is distinguished in hydrographical respects by its rapidly and widely fluctuating temperature and salinity. Certain writers have objected to the validity of this zone as such, on the ground that all its character organisms are also normally to be met with deeper down; this, however, merely reveals a lack of knowledge as to the true state of the case. We may in the first instance take a species which has been utilised in several works for giving the zone in question its other name; to wit, Balanus balanoides Linné. This species does not normally penetrate deeper down. In this connection, however, we are naturally more interested in the characteristic hydroids; which are: Coryne pusilla, Clava multicornis and Laomedea flexuosa. These species are altogether restricted to the tidal zone, and their occurrence in deeper water in the open sea must be regarded as an anomaly, unless due to erroneous identification on the part of the investigator. It is likely that also other species, especially certain Corync, should be grouped among the character forms of the tidal zone, but we have not yet sufficient data to assert this as a fact. The mentioned species are so completely restricted to the area in question, — which is not rich in species on the whole — that we are fully justified in distinguishing the tidal zone as a separate area with a fauna of its own. The deeper zones are, from the character of the investigations, somewhat less strictly defined. It would nevertheless seem that species such as Eudendrium Wrighti, Sertularella rugosa, and Lao- medea geniculata are altogether restricted to the Laminaria zone, while Dyzamena pumila is common to the shallower part of this zone and the tidal zone. The great bulk of the hydroids commence to appear in the lower parts of the laminaria zone, reaching their most luxuriant occurrence in the red alga zone and the lower parts of the littoral region. On passing down beyond about 600 metres depth, however, the lower limit of what may be called the “coast bank region”, we encounter a sudden and very marked decrease in the number of hydroids; below this limit, their occurrence must be called more sporadic, and there are only a few unique species which have their chief occurrence at greater depths. The deep-sea species in question, which have their habitat down here, exhibit also, in each case, a merely sporadic occurrence, — though we cannot, of course, entirely disregard the possibility that this apparent state of things may in re- ality be due to lack of sufficiently exhaustive investigations in the proper localities. A clear indica- tion of the inadequacy of our knowledge as to these deeper parts of the sea floor, even in the North Atlantic, is afforded by the “Ingolf” expedition’s unexpected finding of species such as Branchiocerian- thus reniformis, Zygophylax biarmata, Grammaria conferta, Polyplumaria profunda, and Sertularella amphorifera close south of the submarine ridges in Davis Strait, Danmark Strait, and between Ice- land and the Faroe Islands. With the paucity of available material, it is of but little interest to go into details regarding the bathymetrical distribution of the species. On the other hand, it is well worth while to consider 24% 180 HYDROIDA II the extent of certain horizontal areas of distribution, and we may first of all endeavour to obtain a clearer idea as to what is commonly known as the boreal region, the definition of which at times appears to be somewhat vague. In the case of the hydroids, the data on record furnish valuable hints, as will be seen from the following. Theoretically speaking, the northern limit of the boreal region should be drawn as the bound- ary where southern species of general occurrence in northern waters cease their northward progress, while similarly, the southern limit should mark the extreme margin of the arctic-boreal species’ distri- bution. It should, moreover, constantly be borne in mind that the boreal area is decidedly a “mixed” Sort terecsesences 200 MM, Sou oe es VOOLe tm are 000M, Scapteasesosssamse1a COO MN. Fig. XC. The occurrence of Nemertesia antennina, Dynamena pumila, and Thwaria thuja, three species which are common in more southern European waters, but which only have been found in high arctic waters quite exceptionally. (The red line approximately indicates the limit of the cold area). area; strictly boreal species are extremely few in number, among hydroids as among other animal groups, and will in many places penetrate out beyond the limits of the narrower region. — As ex- amples of southern species extending up to the frontier of the arctic areas we may take for instance Nemertesta antennina, Dynamena pumila, and Thijarta thuja, These three are practically never found in true arctic waters; where finds have been made, it was always at places where north-going cur- rents render the limits uncertain, or where the varying conditions of the coastal water afford southern species a precarious refuge in some isolated spot within the arctic seas. At such places we may en- counter, for instance, scattered colonies of Dynamena pumila. As a general rule, we find (fig. XC) that these species do not cross beyond the limit of the cold area as indicated by the course of the 0° isotherm. At the same time it should be noted that the mentioned species are by no means infre- HYDROIDA II 181 quently met with in Davis Strait, which is thus proved to belong, at any rate in part, to the boundary waters of the boreal region. Yet the species penetrate only quite exceptionally into the west Green- land fjord area, which must be regarded as purely arctic, partly on account of the intermixture of melting water from the glaciers, and partly owing to the north-going branch of the East Greenland Polar Current, which turns round Cape Farewell and runs some distance up the coast. Here we still find Dynamena pumila sporadically, probably because the investigations were carried out at a time when the summer heat had brought the surface temperature up a little, enabling the species just to exist for a brief while, and under difficulties. Not until we reach the waters between Holstensborg I So 600m. popes JOM pee Se ME Fig. XCI. The occurrence of Halectum muricatum, and Sertularella tricuspidata, two arctic species which penetrate into the southern parts of the boreal region. (The red line approximately indicates the limit of the cold area). and Egedesminde do the boreal elements in the coast fauna become more pronounced. In Danmark Strait, between Greenland and Iceland, we see that the finds group themselves closer as soon as we pass south of the o° isotherm, where the depth conditions are more favourable. Despite their positive bottom temperature, the shallower North-Icelandic waters seem to take a more arctic character, though this may, as we shall presently see, perhaps be equally well explained as due to insufficient investi- gation. Between Iceland and the Faroe Islands, the species move up to the verge of the cold area, but do not pass it. And the whole of that part of the Norwegian coastal banks which falls within the limits of the chart presents an entirely boreal character. Turning now to the other side, and taking the distribution of the arctic-boreal species Ha/e- ctum muricatum and Sertularella tricuspidata, several peculiarities are also here apparent (fig. XCI) 182 HYDROIDA II Both species occur in Davis Strait, very commonly on both sides of the o° isotherm, but do not go deeper down from the coastal banks. Both, however, are apparently entirely lacking along the east coast of Greenland south of 76° N. This may be due to paucity of investigations, but it would seem likely that the reason is rather to be sought in the fact that the water, owing to extensive interming- ling of fresh and ice-cold glacier water is poor in suitable forms of nourishment, and unfavourable to the growth of hydroids generally. Altogether, only a very few hydroids have been found along the range in question, the finds in question invariably consisting of but few and small colonies. The apparent absence of the mentioned species in North Iceland waters, on the other hand, would seem KTR ee SSS 600m. Crepe tooom. Sen POON Fig. XCII. Localities of the arctic deep sea species IZyriothela phrygia OQ, and Corymorpha groenlandica O, and of the southern, exotic guests Grammaria conferta coi Zygophylax brarmata +, Polyplumaria profunda ®, Cladocarpus Diana g, Sertularella amphorifera m, and Sertularia (2) tubuliformis t- (The red line approxim- ately indicates the limit of the cold area). rather to be due to lack of sufficient investigation; it is difficult to find any other explanation. The frequent occurrence of the species round all the remainder of Iceland’s coast shows that the range in question must as a whole be included in the boreal area; there is no indication of warmer tendency at any place on the true coastal banks here. The ridge between Iceland and the Faroe Islands, and the waters round the latter down to 600 metres’ depth must be taken as belonging to the boreal region, as also the western Scottish waters. The North Sea also is boreal, and the Norwegian coast to the extent shown on the chart. Before concluding this characterisation of the boreal area, two other geographical groups of less frequently occurring hydroids should be considered. ‘These are the deeper-living inhabitants of the cold area, represented by AZyriothela phrygia and Corymorpha groentandica, and the exotic warm- HYDROIDA II 183 water species of the Atlantic, found here and there in the waters investigated (fig. XCII). MJyriothela phrygia is apparently an easterly arctic species which penetrates out to the southern limit of the cold area; it has in a single instance been taken on the southern, deep slope of the Wyville-Thomson Ridge, brought thither probably by larval transportation. Corymorpha groenlandica moves out every- where to the boundary, and has once passed beyond it, in Davis Strait, on the Store Hellefiskebanke, and between Iceland and the Faroe Islands, probably likewise as a result of larval transportation. Both species are, moreover, met with in a single isolated spot far up in the boreal region, to wit, in Trondhjem Fjord, where they must probably be regarded as relicts — The opposite group, the exo- tics, will be represented by Gvammaria conferta, Zygophylax biarmata, Polyplumaria profunda, and Sertularella amphorifera. One or two of them may in southern localities exhibit a shallower occur- rence; here in the north, however, save for a single find of Polyplumaria profunda up in Danmark Strait, they are not met with beyond the 600 metre curve, nor within the true boreal region. A study of the hydroids leads then to the result, as seen from the instances given, that the limits of the boreal zone as against northerly or arctic waters must be drawn along the o° isotherm; to the south by the southern side of the ridges along the 600 metre curve. The boreal region ex- tends thus from far up in Davis Strait, where, however, it extends only in a very few places in to the coast of West Greenland, across the highest part of the submarine ridge into Danmark Strait, round the coasts of Iceland, including also the plateau between Iceland and the Faroe Islands, the Faroe Islands Banks, the western Scottish waters, and the North Sea and the Norwegian coast pla- teaus (vide charts). Practically speaking, the region embraces all the coast banks of the waters in- vestigated, down to 600 metres, save for the upper 200 metres of the Greenland banks. On comparing the results here arrived at with the lines laid down in Appelléf’s" and vy. Hofsten’s2,3 fundamental works on Crustacea and Echinoderms, we find that they agree very closely therewith. We have, however, here disregarded the mixed areas, which in the works referred to are strongly emphasised. The “boreo-arctic” area, where arctic and boreal elements appear in equal pro- portions, should strictly speaking doubtless comprise the upper parts of Store and Lille Hellefiske- banke, possibly also Fylla Banke, West Greenland, while the north Icelandic coastal region likewise seems to belong to the same. The second mixed area, which according to Appelléf includes the southern parts of the North Sea, the English Channel, and the Irish Channel, should be characterised by a very marked intermixture of southern, Lusitanian or Mediterranean species. It has previously been pointed out that hydroids only penetrate in small numbers down beyond 600 metres depth. It might therefore be objected that the southern boundary of the boreal region as against the Atlantic will in the case of other animal groups be found to follow a deeper curve than here indicated. In comparison therefore, we should also include arctic-boreal species of other animal groups which are more eurybathic. It will here suffice to refer to v. Hofsten’s charts for Ophiocten sericeum and Spirontocaris Gaimardit; they show the same features as the corresponding hydroid spe- cies, and the same southern limits for the boreal region at about 600 metres’ depth. t 1906, Die dekapoden Crustaceen. Meeresfauna von Bergen, Heft 2 und 3. Bergen. 2 1915, Die Echinodermen des Hisfjordes. Zoologische Ergebnisse der schwedischen Expedition nach Spitzbergen 1908. Teil II. Stockholm. 3 1916, Die decapoden Crustaceen des EHisfjordes. Ibid. Teil II. Stockholm. 184 HYDROIDA II One risk attaching to the insertion of the mentioned boreo-arctic and Lusitanian mixed areas lies on the one hand in the fact that by such further division, the whole arrangement is rendered less easy to survey and handle. If, however, other and more essential advantages were procured by so doing, we should naturally not hesitate to accept the biogeographical sub-areas in question But here a very serious difficulty makes itself felt, more particularly on considering the group of hydroids as a whole, to wit, the question of how far up in the boreal area — sensu laterior — the intermix- ture of southern elements takes place to such a degree that the waters concerned should be regarded as a mixed area. By way of illustration we may take the distribution of the families Plamularude 200 m. SeSeSOOUONGe fooom, Secor mots tre ven 2 OOOITT. Fig. XCIII. Finds of Plwmulariidae in the Northern Atlantic. and Avlaophentide, the members of which without exception have their chief occurrence in warmer and more southerly waters, and must in the boreal region be regarded as southern visitors, even though some few of them, such as Nemertesta antennina, and Kirchenpaueria pinnata, may here and there occur in considerable numbers. We should note then, that Plamulariide (fig. XCIII) which save for one or two exceptions belong to the upper 300 metres, are found —- and found very frequently — in the North Sea and along the west coast of Norway, including the Trondhjem Fjord, round the Faroe Islands, along the east, south and west coasts of Iceland; indeed, several species have even been met with several times on the boreo-arctic Lille Hellefiskebanke in Davis Strait. Judging from the family Plumularide then, we come to the result that the Lusitanian element plays a very prominent part in the heart of those areas which we have hitherto designated as the boreal; so much so indeed, that it would be necessary to place the greater part of the tracts concerned in the boreo-lusitanian mixed area if we were to follow Appelléfs principles to their logical conclusion. Taking now again the HYDROIDA II 185 family Aglaopheniide (fig. XCIV) we must first of all bear in mind that we are here dealing with the hydroid family which contains most true deep-sea species, so that we get a picture essentially different from the previous one. Yet there are also various resemblances observable. The boreal bottom region is, as will be evident from the foregoing, a restricted part of the typical coast bank region which runs down to about 600 metres depth. Up in this region, Aglaophenide penetrate more rarely, but are yet not infrequently met with in the North Sea and along the coast of Norway, and may even in certain places be character forms, as for instance in the deep parts of the Trondhjem Fjord, where there is much current. The numerous finds group themselves about the Wyville-Thom- coctiocetncecretis PLO (Gb ) 9 a Se Oe 600m. —— OO ONT. eee OO it, Fig. XCIV. Finds of Aglaopheniidae in the Northern Atlantic. son midge, and of these, about half lie, mirabile dictu, down in that part of the cold area which juts out into the Faroe Channel. In Danmark Strait, also, the finds are gathered about the top of the threshold, and distribute themselves from here round the north side of Iceland. In Davis Strait, the finds are closest in the north-eastern part of the cul de sac running from the Atlantic Deep up the western side of Greenland to the north side of Lille Hellefiskebanke. In this manner then, the intermediate parts between the aforementioned areas, where the strong intermixture of Plwmulariude sets its mark on the fauna, are levelled out. And to be entirely consistent, we should perhaps also, in the Faroe Channel, include a lusitano-arctic mixed area. The data here given serve to show that the establishment of the mentioned mixed areas, the boreo-arctic and the boreo-lusitanian, is attended by considerable drawbacks. No boundary of any region, of course will ever be perfectly clear and sharp, especially in the case of bottom forms. There _ are too many factors to be considered, with the result that the frontier as a matter of fact comes to The Ingolf-Expedition. V. 7 24 ie 156 HYDROIDA II consist of a more or less broad belt, and such belts or mixed areas may under special circumstances attain relatively considerable extent, while in other places they may be quite narrow. We must also remember that the boreal region in itself is the mixed area par excellence, and has practically not a single species to itself, which makes it even more difficult to say what mixture percentage should be taken as limiting the extra mixed areas, the boreo-arctic and the boreo-lusitanian. The maintenance of these will as a matter of fact be to some extent a matter of arbitrary preference. The factors exerting principal in- fluence in the formation of the mixed areas are the positive transportation and the passive restriction of the at- tached organism to the spot once adopted. The latter factor presents no difficulty; if a hydroid colony has once settled down at a given spot on the bottom, then it cannot change its si- tuation, even though the conditions under which it is there called upon to live prove unfavourable. A submarine wave may have produced suitable con- ditions at the time of attachment, af- ter which a change for the worse sets in. If the colony manages to thrive in spite of this, it will then depend on its propagation whether the species becomes indigenous or not. It is pro- bably the question of propagation which has prevented Piuwmulariude and Ag- laopheniude from becoming indigenous Fig. XCV. Currents of the Norwegian Sea in the Norwegian Sea area; save for (after Nansen and Helland-Hansen). Z 4 ‘ a few species, they must evidently be constantly recruited from without. This renewal takes place in the case of certain species, which lack suitable active motive apparatus, by passive transportation. The transport of grown colonies is here practically speaking out of the question; these animals, we know, attach themselves normally~ to the sea bottom itself, or to other colonies already attached thereto. It is therefore larval transportation which plays the chief part'. How long the larval development takes in these forms before they at- tach themselves to the bottom we do not know; probably the time varies,} being doubtless dependent upon external physical conditions; under certain circumstances it would seem that it may extend over a very considerable period. « Cf. Appelléf 1905, Havbundens Dyreliv, Norges Fiskerier I, Norsk Havfiske. Bergen p. I14. HYDROIDA II 187 The explanation of the distribution in these two families must therefore be sought in the current conditions, and we here obtain a very good idea in the case of Aglaophenude. The currents in Davis Strait have as yet been only very little investigated, but we know that there is an atlantic current moving up from the deep towards Store Hellefiskebanke and thus depositing larvee in the cul de sac before mentioned. In the case of the Norwegian Sea, the currents are better known. On glancing at the chart (fig. XCV) and comparing it with the occurrence of Aglaopheniide, the solution is at once apparent. An atlantic current runs northward in the eastern part of Danmark Strait and sends a branch thence along the north side of Iceland aud then southward along the east coast; this branch will thus earry larvee from Danmark Strait and deposit them here and there aiong the coastal banks north and east of the island, where some few of them are able to develope further. This at once explains the scattered occurrence of Aglaopheniide in these waters. The main force of the northgoing atlantic current, however, is concentrated in the Faroe Channel, and here carries the larvee in over the Wyville-Thomson ridge. Along the north side of this ridge, then, we find the heaviest “rain” of exotic larvee in the Norwegian Sea, and here also the greatest percentage of indi- viduals probably capable of developing further, provided they can stand the immersion in the icy waters of the cold area at all. A branch of the same current runs southward along the east coast of Scotland and England, causing a scattered occurrence of Aglaophenide able to develope in shailower water, such as species belonging to the genera Aglaophenia and Thecocarpus. Other larvee drift farther on with the main current, and sink to the bottom on the Norwegian coast plateaus, or the edges of the same, or are occasionally carried as far up as Spitzbergen, whence several finds of Aglaophenude have been recorded, where offshoots from the Atlantic current break in over the plateaus in the shal- lower Murman Sea. It would be of no value here to group the species investigated according to the separate geo- graphical categories. Such arrangement has been made several times in recent works by Kramp (1914) and myself (1909 and later works). It should merely be pointed out that purely boreal hydroids are extremely rare, if indeed we can, after exhaustive investigation, maintain any such at all. We may now proceed to a closer comparison of the hydroid fauna as it appears in the areas represented by Greenland, Iceland and the Faroe Islands. With regard to the two first-mentioned areas, surveys have recently been published by Kramp (1914), and Semundsson (1911); the latter, however calls for certain corrections, and there are also some few additions to be made. Of the species here dealt with, the following have been met with in West Greenland waters (species new to the area are indicated by a *). *Coryne Lovent Monobrachium parasitum Eudendrium annulatum Myriothela phrygia *“Hydractinia Sarsit — capillare Tubularia indivisa = echinata Lajfea dumosa* Corymorpha groenlandica *Perigonimus abysst — fruticosa *Branchiocertanthus reniformis =: VOSCUS — gracillima ? Clava multicornis Eudendrium ranium Toichopoma obliquiem t In the previous chapters the name has erroneously been spelt Za/oéa. HYDROIDA II Grammaria ser pens a = conferta = abtetina — ZINMLEV SA Lictorella pinnata Stegopoma plicatile Cuspidella humilis Lajfoéina maxima Campanulina turrita Calycella syringa Tetrapoma quadridentatum *Halecium scutum — curvicaule — muricatum — labrosum —_ tenellum Flalectum minutum *Polyplumaria profunda Nemertesia antennina *Polynemertesia gracillima Aglaophenopsis cornuta *Cladocarpus integer — Sovmosus Thecocarpus myriophyllum Sertularella tamarisca — tricusprdata — polyzontias — rugosa = tenella Diphasia fallax — Wandeli Dynamena pumila Abietinaria abietina — hlicula Sertularia tenera _ Fabrici _- mirabiles Thoyaria tha _ laxa _ alternitheca Campanularia volubitis — verticillata = groenlandica _ Speciosa Campanularia integra Laomedea longissima — hyalina Bonneviella grandis By comparison with Kramp’s list (1914) it must be noted, that the following species are synonyms: Garveta groenlandica | a ae oe = Perigonimus roseus Perigonimus roseus } Flalectum Beant = Halecium scutum Plumularia groenlandica = Polynemertesia gracillima Cladocarpus Flolmt = Cladocarpus integer New to the area are thus in reality only the five species Branchiocerianthus reniformis, LLydractinia Sarsu, Perigonimus abysst, Grammaria conferta and Polyplumaria profunda, Of East Greenland species, the material contains the following: Tubularia regals Calycella syringa Diphasia fallax *Perigonimus abysst Tetrapoma quadridentatum Abietinaria abtetina a Sertularia tenera flydralimania falcata = VOSCUS Halectum curvicaule Eudendrium rameum = muricatum Lafea fruticosa co labrosum Thiyaria thiya — gracillima — tenellum _ laxa Toichopoma obligqueum =— minutune Campanularia volubilis Grammaria serpens *Cladocarpus integer — verticillata - abietina Sertularella tricuspidata — groenlandica _ LIMLETSA - polyzonias — integra Cuspidella humilis zs — tenella Laomedea longissima Lafoéina maxima HYDROIDA II 189 Taking into consideration the above noted synonyms, only three species are new to the area, viz: Halecium labrosum, Cladocarpus integer and Sertiularella tenella. It should here further be noted that the new investigations have especially augmented the number of species south of 70° N. The East Greenland waters between 60° and 70° N. seem to be very poor in hydroids, even right out on the slope towards the deep of the Frozen Sea, and the Atlantic deep. According to Kramp (1914) there are hitherto recorded 88 hydroids from Greenland. In the previous sections we have pointed out the following synonyms, which are given in the mentioned list: Corymorpha groenlandica | : = Corymorpha groenlandica — islandica J Perigonimis roseus | eee : : = Perigonimus roseus Garveia groenlandica J Flalectum Beant = Halectum scutum Lafota fruticosa | — pocillum = Lafea fruticosa, forma genuina and forma grandis — grandis | Serlularia polyzonias \ : ‘ : = Sertularia polyzonias, forma ¢ypfica and forma gigantea — gigantea } Plumularia groenlandica = Polynemertesia gracillima Antennularia antennina = Nemertesia antennina Cladocarpus cornutus Aglaophenopsis cornuta -- Flolmit = Cladocarpus integer This means, then, a reduction of five in the number of species. On the other hand, the five new species from the West Greenland area are entirely new to the fauna, so that the number of spe- cies is still 88, or, taking Lafea /ruticosa forma grandis and Sertularella polyzonias forma gigantea as distinct species, the number is increased to 90. The recent studies have thus not greatly increased the number of species, nor was this to be expected. The greatest increment of species new to the fauna was to be expected in Davis Strait, and the few investigation stations made there by the “Ingdlf” are entirely covered by the later expeditions with the “Tjalfe”, the excellent treatment of which material has contributed in an essential degree to our comparatively close knowledge of the hydroid fauna in West Greenland waters. Passing on now to the fauna area of Iceland, we find in the material the following species belonging to this section: Coryne Sarsit Corymorpha nutans Bougainvillia conferta * — pusilla -- glacialis Eudendrium,. rameum Myriothela phrygia : =— eroenlandica — ramosum Tubularia pulcher *Clava multicornis = capillare -- mmdivisa *Hlydractinia Sarsit Lafea dumosa _ larynx _ echinata — fruticosa 190 Lajfea gracillima Grammaria serpens abietina — TMMLEVSA Lictorella pinnata *“Lygophylax biarmata *Stegopoma plicatile Cuspidella humilis Lafotina maxima Calycella syringa Flalectum halectnum Beant scultum curvicaule muricatium labrosum tenellum —— minutun Kirchenpaueria pinnata Plumularia setacea — Catharina Polyplumaria frutescens “2 — flabellata zs = profjunda HYDROIDA II Nemertesia antennina VAMOSA Polynemertesia gracillima *Halicornaria campanulata *Nematocarpus ramuliferus *A glaophenopsis cornuta *Cladocarpus integer Ba a Sormosus * bicuspis *Thecocarpus myrtophyllum Sertularella tamarisca Sertularia cupressina lenera Fabricit mirabilis Hydrallmania falcata Thujaria thea lonchitis laxa alternitheca arctica carica ~- tricuspidata Campanularia volubilis = amphorifera Campanularia verticillata - polyzonias a groenlandica — Gayi — mtegra — VUgOSA — Finckst Diphasia fallax — Johnstone oe Wandelt Laomedea flexuosa — rOSACEA — geniculata * — ~~ attenuata longissima Dynamena pumila _- hyalina A bretinaria abtetina — gracilis filicula (2) fusca Bonneviella srandts. 5} An examination of Semundsson’s material and list (1911) will show that it contains the following synonyms: Clava squamata Coryne vermicularis Jruticosa Syncoryne eximia Syncoryne Sarsit Auliscus pulcher Amalthea tslandica Corymorpha glacialts Eudendrium rameum rigidum ? Dicoryne conferta Laomedea gelatinosa longissima Clava multicornts Coryne pusilla Coryne Sarsit | Tubularia pulcher Corymorpha glacialis Eudendrium rameum — Bougainvillia conferta = Laomedea longissima i /.- HYDROIDA II 1QI Lafoéa pygmea care alt, = Lafea gracillima — gracillima — pocillum | — symmetrica = Lafea fruticosa forma genuina and forma grandis — Sfruticosa | Filellum serpens Grammaria serpens Lictorella Levinsent = Lygophylax biarmata Sertularia cupressina | s : = Sertularia cupressina —_ argentea } — pumila = Dynamena pumila Diphasia fusca A btetinaria (?) fusca = abtetina = Abtetinaria filicula Antennularia antennina = Nemertesia antennina = vamosa = = vaMOSA Plumularia pinnata Kirchenpauerta pinnata _ eracillima = Polynemertesia gracillima — Srutescens = Polyplumaria frutescens Thecocarpus radicellatus = Thecocarpus myriophyllum Cladocarpus Flolmt = Cladocarpus integer The synonyms noted reduce the number of species by g; furthermore, Semundsson (1902, 1911) notes Zurris neglecta Lesson, which here probably represents a young colony of Clava multi- cornis, and Diplura fritillaria (Haeckel) = Coryne fritillaria Steenstrup, an altogether uncertain species (cf. Part I, p. 23). Renewed investigations must also decide what species is concealed under the name Perigonimus repens. Altogether, we have then to reduce the go species noted by Semundsson to a certain 77. But the geographical details for these species are highly uncertain, as the determina- tion has on revision often proved erroneous. In the revised collections, for instance, we find under the old label “7heyaria lonchitis” specimens of Thujaria lonchitis, Thigaria laxa, Thiyaria alternitheca, and Thyaria carica, while under “Laomedea flexuosa” we find labelled, besides specimens actually belonging to that species, also others of Laomedea geniculata and Laomedca longissima. On the other hand, spe- cimens of Laomedea longissima are distributed under the names of Laomedea flexuosa, Laomedea long- issima, and Laomedea gelatinosa — taking examples at haphazard. The detaiis are apparent from the notes under the separate headings. Even though the detailed records thus leave much to be desired, we have nevertheless a pretty fair survey of the species comprised under the area as a whole. The investigations have now added the following 14 new species to the list: Corymorpha groenlandica Polyplumaria profunda Cladocarpus bicuspis Flydractinia Sarsit Halicornaria campanulata Sertularella amphorifera Stegopoma plicatile Nematocarpus ramuliferus Diphasia attenuata Flalecitum scutum Aglaophenopsis cornuta Thijaria alternitheca Polyplumaria flabellata Cladocarpus formosus 192 HYDROIDA II We have thus reached a total of g1 species certainly known. The nature of the additions is not uninfluenced by the fact that the investigations were largely carried out on the deeper slopes of the coastal banks, so that southern and eurytherm species form the majority of the species thus added to the fauna list of the island. We now come to the fauna of the Faroe Islands area. The species from here which are included in the material cover the entire range of our present knowledge as to the hydroid fauna of this sec- tion. We have here the foliowing 57 species: Coryne pusilla Tubularia indivisa —_ larynx Clava multicornis Merona cornucopiae Bougaimnvillia conferta Perigonimus repens Eudendrium rameum — Wrighti — capillare Lafea dumosa — fruticosa — gracillima Grammaria serpens = abietina Calycella syringa Flalectum halecinum — scutim — muricatum Flalecium labrosum — tenellum Kirchenpaueria pinnata Plumularia Catharina Polyplumaria frutescens Nemertesia antennina = ramosa Nematocarpus ramutliferus Cladocarpus formosus Thecocar pus myriophylium Serlularella tamartsca — tricuspidata — polyzonias ase Gaye = tenella — TULOSA Diphasia fallax — VOSACEA Dynamena pumila Abtetinaria abietina = filicula = (?) fusca Sertularia cupressina — temera Hydralimamia falcata Thijaria thuja — laxa Campanularia volubilis — verticillata — integra — Flinckst —- Sohnstont Laomedea flexuosa -- geniculata -- longissima -— hyalina — eracilis Bonneviella grandis Along the deepest portions of the slope of the banks, the following five were found: 7wdbzlaria regalis, Corymorpha glacialis, Corymorpha groenlandica, Lictorella pinnata, and Sertularella mirabilrs ; save for the last but one, all of these belong to the cold area; finds lie so far out in the periphery that it is doubtful whether they should really be counted as belonging to the fauna of the Faroe Bank. If we do so, then we have up to now 62 species recorded from the Faroe Islands sec- tion, but the number will doubtless be increased by further study. We must at any rate expect to find the following six species at the Faroe Islands, since they are found, and partly also frequent, in Iceland waters and round the British Isles: Coryne Sarsii, Corymorpha nutans, Hydractinia echinata, Cuspidella humilis, Plumularia setacea, and Diphasia attenuata. This, however probably by no means exhausts the list of species, and in particular we may expect to find more southern forms as more or less sporadic visitors to the Faroe Islands. A comparison between the fauna of the three areas shows that the Greenland area includes II species not known from Iceland or the Faroe Islands. hese are: HYDROIDA II 193 Coryne Lovent Perigonimus abysst Campanulina turrita Tubularia regalis _ VOSEUS Tetrapoma quadridentatum Branchiocerianthus reniformis Eudendrium annulatum Campanularia speciosa Monobrachium parasitum Toichopoma obligueum Of the species mentioned, however, Coryze Lovent is also known from the North Sea as far down as the Danish waters, and it would seem likely that it is identical with the polyp Coryne fri tillarza Steenstrup, and thus belongs to the Iceland fauna area. Perigonimus abyssi and Perigonimus roseus extend southward along the west coast of Scandinavia at any rate as far as Bohuslin; Auden- drium annulatum has been recorded both in Norwegian and in British waters, and Campanalina tur- vita has been found in Irish waters, near Belfast. In the case of these species it is thus natural to suppose that they will also prove to occur in the intermediate areas at the Faroe Islands and Ice- land. The geographical character of Branchiocertanthus reniformis is altogether unknown. We have then remaining, as peculiar to Greenland, the species Zudwlaria regalis, Monobrachium parasitum, Toichopoma obliguum, Tetrapoma quadridentatum, and Campanularia speciosa, high arctic or panarctic species which appear to be of particularly stenothermic character. A far more unexpected state of things is met with in the Iceland area. The characteristic species here are: Tubularia pulcher Plumularia setacea Sertularella amphorifera Corymorpha nutans Polyplumaria flabellata Diphasia attenuata _ glacials Flalicornaria campanulata Thujaria carica Zygophylax biarmata Cladocarpus bicuspis Among these there are, as far as our knowledge at present goes, two easterly, panarctic spe- cies, to wit, Corymorpha glacialis and Thiyaria carica. These species thus characterise the Icelandic fauna area as the frontier tract for east-arctic species. Similarly, the occlitrence of the Greenlandic Thyaria alternitheca suggests that the area in question is also a boundary region for westerly, arctic- boreal species. The list given is, however, most striking from the many exotic warm-water species which it contains. The Iceland fauna area has, as a matter of fact, at present several more such species than the Faroe Islands area. It would thus seem as if the influence of the warm atlantic coy teas the southern slope of the Iceland grounds is more immediate. How far the Rockall Banks may be partly responsible for the somewhat less marked immigration of warmer atlantic species to the Faroe Islands area cannot be stated with certainty, but there are several indications that such might well be the case. - The Faroe Islands area is distinguished by only two species, AZerona cornucopie and Eudendrium Wrightt, as against the two other areas; these two species contribute, however, but little to the char- acterisation of the waters in question as we know them at present. The most striking feature of the true Faroe Bank area is another, negative character, to wit, the lack of high arctic or panarctic species. Only deeper-living arctic species such as Zuédelaria regalis, Corymorpha glacialis, Corymorpha groenlandica, Grammaria immersa, Stegopoma plicatile, and Sertularia Fabricit verge now The Ingolf-Expedition. V. 7. 25 194 HYDROIDA II and again on to the deepest parts of the Faroe Bank, where they rise from the cold area at the eastern slopes of the ground. The community which is characterised by the last-named species, and which further includes Lafea fruticosa torma grandis, Lafea gracillima forma elegantula, and Sertularella polyzonias forma gigantea, has its home throughout the whole of the arctic regions; farther to the north, we find it in shallower water, in the southern parts of the cold area in deeper; here also, it penetrates out to the Wyville Thomson ridge in the Faroe Channel, where warm atlantic water-masses present a barrier to its further progress. Only a single find of AZyriothela phrygia has been made on the southern slope of the Wyville Thomson ridge. These species thus characterise the Norwegian Sea Deep, and show the marked difference between it and the Atlantic deep sea region. The limit of their occurrence here in the south follows on the whole very closely the o° isotherm. True these species may at times, in higher latitudes, occur in water layers of higher tempe- rature, but this can have no effect on the limitation of the cold area as a whole against the boreal and atlantic tracts. A biogeographical peculiarity is seen in the Trondhjem Fjord, where hydrogra- phical conditions of an atlantic character prevail, nevertheless we here find AZyriothela phrygia, Tu- bularia regalis, Corymorpha groenlandica, and Stegopoma plicatile thriving excellently; indeed, Zzdzla- ria regalis, and Stegopoma plicatile even appear as local character forms in the otherwise purely atlantic Lophohelia-biocoenoze. This can apparently only be explained by regarding the species as relicts in the fjord, which have been able to adapt themselves to altered conditions there. This exception, how- ever, cannot alter their general character as arctic species. On the other hand, we find in the material also species which are not able to penetrate beyond the limits of the warm atlantic water-layers, and which are thus entirely lacking in the boreal region. These species emphasise still further the marked difference between the fauna of the Atlantic abyssal region and the cold area. We may here in particular point out Gvammaria conferta, Zygophylax biarmata, Polyplumaria profunda, and Sertularella amphorifera, typical representatives of the warm atlantic deep-sea fauna. The finding of these so far to the north shows us on the one hand how uniform the fauna must be throughout the deep region of the Atlantic, but also, on the other hand, how little we yet know as to the geographical distribution of the bottom fauna, and what great and tempting tasks still await the investigator in thoroughly elucidating the question of bottom fauna even here in the North Atlantic. HYDROIDA II V. List of the genera treated, and type-species. (Nomina conservanda), Coryne, Gaertner Myriothela, M. Sars Tubularia, Linné Corymorpha, M. Sars Branchiocerianthus, Mark Clava, Gmelin Merona, Norman. Monobrachium, Mereschkowsky. Hydractimia, van Beneden. Bougainvillia, Lesson. Perigonimus, M. Sars. Eudendrium, Ehrenberg. Lafea, Lamouroux. Toichopoma, levinsen. Grammaria, Stimpson. Lictorela, Allman. Zygophylax, Quelch. Stegopoma, Levinsen. Cuspidella, Hincks. Lafotina, M. Sars. Campanulina, van Beneden. Calycella, Hincks. Tetrapoma, Levinsen. Halecium, Oken. Kirchenpaueria, Jickeli. Plumularia, Lamarck. Polyplumaria, G. O. Sars. Nemertesia, Lamouroux. Polynemertesia, Nov. Flalicornaria (Busk). Nematocarpus, nov. Aglaophenopsis, Fewkes. Cladocarpus, Allman. Thecocarpus, Nutting. Aglaophenia, Lamouroux. Sertularella, Gray. Coryne pusilla, Gaertner 1774. Lucernaria pirygia, Fabricius 1780. Tubularia indivisa, Tinné 1758. Corymorpha nutans, M. Sars 1835. Monocaulus zmnperator, Allman 1888. Hydra mudlticornis, Forskal 1775. Tubiclava cornucopiae, Norman 1864. Alcyonium echinatum, Fleming 1828. Eudendrium vamosum, van Beneden 1844. Perigonimus muscoides, M. Sars 1846. Tubularia vamosa, Linné 1758. Campanularia dwmosa, Fleming 1820. Calycella obf¢qua, Hincks 1874. Campanularia abzetina, M. Sars 1851. Lafoéa pinnata, G. O. Sars 874. Zygophylax profunda, Quelch 188s. Calycella plscatilis, G. O. Sars 1874. Campanularia /emlis, Alder 1863. Lafoéina tenuis, M. Sars 1869. Campanulina tenuis, van Beneden 1847. Sertularia syr7ga, Linné 1767. Calycella guadridentata, Hincks 1874. Sertularia halecina, Linné 1758. Sertularia pzznata, Linné 1758. Sertularia sefacea, Linné 1758. Polyplumaria flabellata, G. O. Sars 1874 Sertularia antennina, Linné 1758. Plumularia gracillima, G. O. Sars 1873. Halicornaria bipinnata, Allman 1876. Halicornaria vamulifera, Allmaun 1874. Aglaophenopsis hirsuta, Fewkes 1881. Cladocarpus formosus, Allman 1874. Sertularia myriophyllum, Linné 1758. Sertularia Alwma, Linné 1758. Sertularia Aolyzonzas, Linné 1758. ty on Monobrachium parasitum, Mereschkowsky 187 7: e a o 7 a a ' no a ¥ : | ‘ ; f eA er t i 7 - . F 196 HYDROIDA I Diphasia, L. Agassiz. Sertularia rosacea, Linné 1758. -Dynamena, Lamouroux. Sertularia pumila, Linné 1758. Abietinaria, Kirchenpauer. Sertularia aéeetina, Linné 1758. Sertularia, Linneé. Sertularia cupressina, Winné 17 58. Hydrallmania, Hincks. | Sertularia falcata, Linné 1758. Thyaria, Fleming. Sertularia ¢heya, Linné 1758. Campanularia, Lamarck. Sertularia voludilis, Linné 1758. Laomedea, Lamouroux. Laomedea flexuosa, Alder 1856. Bonneviella, Broch, Campanularia grandis, Allman 1874. Trondhjyem, 24.—VI.—1917. . ‘ ; 7 si Pewee fre oe, ~ 14. I5- EimE RAT URE. . Agassiz, Al. (1865): Illustrated Catalogue of the Museum of Comparative Zodlogy at Harvard College. North American Acalephae. Cambridge. Agassiz, L. (1860—1862): Contributions to the Natural History of the United States of America, Second Monograph, vol. 3 and 4. Boston. Alder, J. 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London. — (1855): Notes on British Zoophytes, with description of new species. (Ann. and Mag. of nat. Hist., Ser. 2, vol. 15). London. — (1861): A catalogue of the Zoophytes of South Devon and South Cornwall. (Ann. and Mag. of nat. Hist., Ser. 3, vol. 8). London. — (1866): On new British Hydroida. (Ann. and Mag. of nat. Hist. Ser. 3, vol. 18). London. — (1868): A History of the British Hydroid Zoophytes. London. — (1874 a): Notes on Norwegian Hydroida from deep-water. (Ann. and Mag. of nat. Hist., Ser. 4, Vol. 13). London. — (1874b): On deep-water Hydroida from Iceland. (Ann. and Mag. of nat. Hist. Ser. 4, Vol. 13). London. Hincks, Th. (1877): Note on lists of arctic Hydrozoa and Polyzoa, published in the »Annals« for February 1874 and January 1877. (Ann. and Mag. of nat. Hist., Ser. 4, Vol. 20). London. Jéderholm, E. (1907 a): Uber einige nordische Hydroiden. (Zool. Anz. Bd. 32). Leipzig. — (1907b): Zur Kenntnis der Hydroidenfauna des Beringsmeeres. (Arkiv fér Zool., Bd. 4). Stockholm. HYDROIDA II 199 t Jiiderholm, £. (1909): Northern and Arctic Invertebrates in the Collection of the Swedish State Museum. IV. Hydro- iden. (Kgl. Svenska Vet-akad. Handl., Bd. 45). Uppsala & Stockholm. . Johnston, G. (1833): Ilustrations in british zoology. (Mag. of Nat. Hist., vol. 6). London. — (1847): A History of the British Zoophytes. London. Kirchenpauer, G. H. (1884): Nordische Gattungen und Arten von Sertulariden. (Abh. a. d. Gebiete der Naturwiss., her- ausgeg. y. d. naturwiss. Ver. Hamburg, Bd. 8), Hamburg. i Kramp, P. L. (1git\: Report on the Hydroids collected by the Danmark Expedition at North-East Greenland. (Danmark- Eksped. til Grénlands Nordéstkyst 1906— 1908, Bd. V). Kébenhayn. — (1913): Hydroids collected by the »Tjalfec Expedition to the West Coast of Greenland in 1908 and 190g. (Vidensk. Meddel. fra den naturhist. Foren., Bd. 66). Kobenhayn. — (1914): Conspectus Faunze Groenlandicee. Hydroider. (Meddel. om Grénland XXIII) Kébenhavyn. Kin, A. (1909): Sprosswachstum und Polypenknospung bei den Thecaphoren. (Zool. Jahrb. Abt. Anat., Bd. 28). Jena. — (i910): Die Entwickelung der Geschlechtsindividuen der Hydromedusen. (Zool. Jahrb. Abt. Anat., Bd. 30). Jena. — (1911): Uber den Bau einer Thyroscyphus-Art und die systematische Stellung der Gattung Thyroscyphus. (Zool, Jahrb. Abt. Syst., Bd. 31). Jena. — (1913): Entwickelungsgeschichte und Verwandtschaftsbeziehungen der Hydrozoen. I. Die Hydroiden. |Ergebn, u. Fortschr, d. Zool., Bd 4), Jena. Lamarck, /. (1816): Histoire naturelle des animaux sans yertébres. Vol. 2. Paris. . Lamouroux, J. V. F. (1812): Extrait d'un mémoire sur la classification des Polypes coralligénes non entiérement pierreux. (Nouv. Bull. des Sci. Soe. philomat., vol. 3). Paris. — (1816): Histoire des Polypiers coralligénes flexibles vulgairement nommés Zoophytes. Caen. — (4821): Exposition méthodique des genres de lordre des Polypiers, avec leur description et celle des principales espéces, figurées dans 84 planches, les 63 premiéres appartenant a Vhistoire naturelles des Zoophytes d’Ellis et Solander. Paris. Levinsen, G. M, R. (1892): Om Fornyelsen af Ernzeringsindiyiderne hos Hydroiderne. (Vidensk. Meddel. fra den naturhist. Foren.), Kjébenhayn. — (1893 a): Meduser, Ctenophorer og Hydroider fra Grénlands Vestkyst. (Vidensk. Meddel. fra den naturhist. Foren.). Kjébenhayn. — (1893 b): Hydroidae. (Det vidensk. Udbytte af Kanonbaaden )»Hauchis Togter). Kkjobenhayn. -— (1913): Systematic Studies on the Sertulariidae. (Vidensk. Meddel. fra den naturhist. Foren., Bd. 64). K6benhayn. Linne, C. v. (1758): Systema Nature. Ed. 10. Holmiz. — (1767): Systema Nature. Ed. 12, vol. 1. Holmiz. Lorenz, L. v. (1886): Polypomedusen yon Jan Mayen gesammelt yon Dr. F. Fischer. (Intern. Polarforsch. 1882—S3. Die 6sterreichische Polarstation Jan Mayen, Bd. 3). Wien. MacGillivray, J. (1842: Catalogue of the marine Zoophytes of the neighbourhood of Aberdeen. (Ann. and Mag. of nat. Hist., vol. 9). London. Mark, &. L, (1899): Preliminary Report on Branchiocerianthus urceolus, a new type of Actinian. (Bull. Mus. Comp. ZoOl., vol. 32). Cambridge, Mass. — (1899): »Branchiocerianthus« a correction. (Zool. Anz. Bd. 22). Leipzig. Marktanner-Turneretscher, G. v. (1890): Die Hydroiden des k. k. naturhistorischen Hofmuseums. (Ann. naturhist. Hofmus., Bd. 5). Wien. — (1895): Hydroiden yon Ostspitzbergen. (Zool. Jahrb. Abt. Syst, Bd. 8). Jena. Mereschkowsky, C. (1877): On a new genus of Hydroids from the White Sea, with a short description of other new Hy- droids. (Ann. and. Mag. of nat, Hist., Ser. 4, vol. 20). London. — (1878): New Hydroida from Ochotsk, Kamtschatka, and other parts of the North Pacific Ocean. (Ann. and Mag. of nat. Hist., Ser. 5, vol. 2). London. . Myajima, MW. (1900): On a specimen of a gigantic Hydroid, Branchiocerianthus imperator (Allman). (Journ. Coll. Sci. of the Imp. Univ. Tokyo, vol. 13). Tokyo. Nordgaard, OU. \1903): Hydrographical and Biological Investigations in Norwegian Fjords. Bergen. Nutting, C. C. (1900): American Hydroids. Part I. The Plumularidae. (Spec. Bull, Smithson. Inst.) Washington. — (Igota): Papers from the Harriman Alaska Expedition. KXI. The Hydroids. (Proc. of the Washington Acad. of Sei., Vol. 3). Washington. — (1go01 b): The Hydroids of the Woods Hole Region, (Bull. U. S. Fish Comm. for 1899). Washington. Iol. TO4. 105. 106. 119. 120. HYDROIDA II Nutting, C. C. (1904): American Hydroids. Part II. The Sertularida. (Spec. Bull. Smithson-Inst.). Washington. — (1915): American Hydroids. Part II. The Campanularidee and Bonneviellide. (Spec. Bull. Smithson-Inst.). Washington. Oken (1815): Lehrbuch der Naturgeschichte. Dritter Teil: Zoologie, vol. 1. Jena. Pallas, P. S. (1766): Elenchus zoophytorum. Haga-Comitum. Pictet, C. et Bedot, M. (1900): Hydraires proyenant des campagnes de |’Hirondelle. (Rés. des Campagnes sci.... Albert Ier, Fase. 18). Monaco. Ritchie, J. (1907): The Hydroids of the Scottish National Antarctic Expedition. (Transact. Roy. Soc. Edinb., Vol. 45). Edinburgh. — (1909): Note on a rare Plumularian Hydroid, Cladocarpus formosus. (Ann. and Mag. of nat. Hist., Ser. 8, vol. 3). London. — (1g10—1911): Contributions to our knowledge of the Hydroid fauna of the West of Scotland. (Ann. of the Scott. Nat. Hist. 1g910—1911). Edinburgh. — (1912): Some Northern Hydroid Zoophytes obtained by Hull Trawlers; with description of a new species of Plumul- larian. (Proc. Roy. Phys. Soc. Edinburgh, Vol. 18). Edinburgh. — (1913): Note on the type specimen of Plumularia Catharina Johnston, and its so-called »stemless variety«, and on the invalidity of the Hydroid genus Diplopteron, Allman. (Proc. Roy. Phys. Soc. Edinburgh, vol. 19). Edinburgh. Sars, G. O. (1873): Bidrag til Kundskaben om Dyrelivet paa yore Havbanker. (Forhandl. i Vid.-Selsk. i Christiania 1872) Christiania. — (1874): Bidrag til Kundskaben om Norges Hydroider. (Forhandl. i Vid.-Selsk. i Christiania 1873). Christiania. Sars, M. (1851): Beretning om en i Sommeren 1849 foretagen Zoologisk Reise i Lofoten og Finmarken. (Nyt Mag. for Naturvid., Bd. 6). Christiania. — (1863): Bemeerkninger over fire norske Hydroider. (Forhandl. i Vid.-Selsk. i Christiania 1862). Christiania. Schneider, K. C, (1897): Hydropolypen yon Rovigno nebst Ubersicht iitber das System der Hydroidpolypen im Allge- meinen. (Zool. Jahrb. Abt. System., Bd. 10). Jena. Schweigger, A. F. (1820): Handbuch der Naturgeschichte der skelettlosen ungegliederten Thiere. Leipzig. Schydlowsky, A. (1902): Les Hydraires de la Mer Blanche le long du littoral des Hes Solowetzky. (Trav. Soc. nat. Univ. Imp. Kharkow, Tome 36). Kharkow. Stechow, E. (1908): Beitraége zur Kenntnis von Branchiocerianthus imperator (Allman). Inauguraldissertation. Miinchen. — (1909): Hydroidpolypen der japanischen Ostkiiste. I. Athecata und Plumularidae. (Abhandl. der math. phys. Klasse der k. Bayer. Akad. der Wiss. I. Suppl.-Bd.). Miinchen. (1912): Hydroiden der Miinchener Zoologischen Staatssammlung. (Zool. Jahrb. Abt. System., Bd. 32). Jena. — (1913): Hydroidpolypen der japanischen Ostkiiste. IJ. Campanularidae, Halecidae, Lafoeidae, Campanulinidae und Sertularidae, nebst Erginzungen zu den Athecata und Plumularidae. (Abhandl. der math. phys. Klasse der K. Bayer. Akad. der Wiss., III. Suppl.-Bd.). Miinchen. Semundsson, B. (1902): Bidrag til Kundskaben om de islandske Hydroider. (Vidensk. Meddel. fra den naturhist. Foren. i Kébenhayn 1902). Kébenhayn. — (1911): Bidrag til Kundskaben om de islandske Hydroider. Il. (Vidensk. Meddel. fra den naturhist. Foren. i Kében- hayn 191). K6benhayn. Thompson, D’A. IV. (1884): The Hydroid Zoophytes of the »Willem Barents« Expedition 18$1. (Bijdragen tot de Dier- kunde. Aflv to). Amsterdam. Vanhoffen, E. (1909): Die Hydroiden der deutschen Siidpolar-Expedition 1g01—1903. (Deutsche Siidpolar-Expedition 1g0I—Igo3. Bd. 11, Zool. Bd. 3). Berlin. Verrill, A. FE, (1873): Brief contributions to Zodlogy, from the Museum of Yale College. (Amer. Journ. of Sci. and Arts, Ser. 3, vol. 5). New-Haven. — (1879): Notice of recent additions to the marine fauna of the eastern coast of North America. (Amer. Journ. of Sci. and Arts, Ser. 3, vol. 17). New-Haven. INDEX Abzetinaria abietina.........-.+++++> II 177, 188, 190, 192, 196 — JOE sb so oe a0 8 Condo Il 118, 219, 129, 188, 199, IgI, 192 — (N/ZNAE 3.04 0ag boo booms II 120, 144, 190, IgI, 192 Aglaophenia bicuspis............--- Il 89 _— LOLMMOS Aye tele si eyye es) -) =e Il 86 — WOM bohoooeess eee llEs233 = DPT dogg ogo0doNaeOe Il 195 — HOMAGE 6 ON BED be US Il 94 Aglaophenopsis cornuta ..........-.- II 63, 77, 188, 189, 190, IgI — PRLESULCL eicats setenv eke oie II 195 -- PDOLELE selena te octets Il 80 — VOM 5 Sollee ban OOo II 8r Alcyonium echinatum .............. 146) L195 Ammaltheeamislandicayes osc 3.0/0) shs I 40 PM DVILELECOMIOIS, Ws fara Sisikvartie © wee wetepere I 10, 38, I 179, 190, 192, 195 Sot PAP ASTEL CA yy tate ere fapevers ayes ayoyets I 38 26 190 192 1g0, 192 192 164, 188, 190, 192, Ig, 192 189, 189, 190 187, 189, HYDROIDA II 202 Clava; SQuamatay mene ntacke ti catereni ay: 1 38. II 190 Cia picophord eae een Il 163 =) Johnston page ee eee score II 163 Corymorpha glacialis ...........+.+. T2728. 32) lle 75 mos 190, 192, 193 — PUOCMLANAICE. |. ae ee ee 22 Iie PUR eee WIPE ates, 182, 183, 187, 189, 191, 192, 193, 194 _ ELIA ODS 8 B UR PORORG OCCU O I 30, gz. 11 174, I90, 192, 193, 195 - [RAT hes og So ODT ODDS Il 175 — SGAE Gecasrocnesbaenes I 29 _ Spitzbergensis.-2.....-- I 33, 36 — VATOOGISIS Senet eerie I 29 Coryne brevicornis eee see te weee esse ns I 13 ==) (KOMI eer a os eee I 16 ==" fritillariay. .2F.f 2 ctciase ste I 23. IL 191, 193 frutiCOSawens a. cmeseae os cries ales I 16. II 190 i LIDPEC SGN rates a teae ate cverency tate ors Mesa) 33) tsps natin He7ChStins sae oasis: I 18 LOUENE Roa ee aol a W355, 23) Ll 1875193, = | pusilla. ota ae aes I 13, 76. IL 179, 189, 190 192, 195 ; Sel Sao ac capeurtacts aan toed Ly 73) 4 ll 1S9;-s190: 192 1 Vern crlanis® aermrnr sora 1 16. Il 190 GCnyptolariay.confertam a.memdenaene ec 1 7 (Guspiaellavhur2its 4 ey a ee Il 29, 188, 190, 192, 195 Wicoryne conterta em ese acee eee: T 50. II 190 DO AOR LEA ER COO OL OE Il 14 a Ure i CO SOU E eT II 113, 190, 191, 192, 193 SS ILL RA Hae a Il 97, 108. 111, 113, 188, 190, 192 a ef MSCOY., a. ce mr eteilee lee Sion, opi Il 191 == rab be NOUNS ony eueceoabones II 133 ——" PURURIA anos GaneOneddobOt Il 97, 109, 112, 190, 192, 196 — tamarisca sis. ae sinicei coe II 96 —— Wandelt setae ee oe II 109, 110, 7, 188, 190 DD OMEN CEDUIIIIA seta sterehe ty orera ented eats II 775, 133, 179, 180, 181, 188, 190, 191, 192, 196 — PATA ALIS Cal faayeyetyer\-vaeteeiey- II 96 — tubnliformis)s..-sj.2 ee II 132 _ aumilateralishaeemets terete II 127, 129 Eudendrium annulatum............. 1 67. II 187, 193 — arbuscular iss sacs I 60 — COPA Er -larersielers ei ctareets I 61. II 187, 189, 192 — Caricum.. eee eee 158 — CONTErtas yee tetera cete I 50 — TACEIMOSUME ne Haya eeleiay I 60 — RAMEUMER I te a emir I 57, 60. II 187, 188, 189, 190, 192 = VLINOSUII En ene wee Lene een I 57, 58, 59. II 189, 195 Eudendrium repens — rakes Ohibuliga nao acineeocr — UAE ss ang Cea gIae ileliuaeSerpen Sierras ele efaetet ratte Garveia groenlandica .............. Gonothyraea gracilis............... — hiyallittaleer ca. thepiete ects — Loyeni Grammaria abietina CUE 6 con acbapodnese5 — TUM ATAL So 8 Sore d JOd Aaae — TODUSta. sees ae ses ei — SCAMS reales ey as SCUDOZES satel eletielee elie! fslteleliet sl Halectum Beant... — minutium = mirabile 1 52 I 58. Il 190 II 2 I 8, 57, 60. 193 Il 16, 191 I 54. IL 188, 189 Il 170 II 179, 192, 190, 192, 195 II 17, 179, 182, 183, 188, 194 IL 20; 21, 922) 1883190; 193 II 18 5 IN ads. pit Il 16, 188, 190, I9I, 192 II 37, 38, 40, 41, 188, 189, 190 Il 49 II 41, 188, 190 Il 36, 39, 40, 41, 190, 192, 195 II 45, 47, 188, 189, 190, 192 II 35, 49, 50, 188, 190 Il 42, 43 Il 43, 47, 181, 188, 190, 192 — RANUMIN rete aaNeketoeetro es Il 49 — OALBTTE done boon DOORN toe II 36 — TEPCuS hess hitecietseteiat II 42 — AS CAILELAET I atstiexerheratstotonereatee Il 49 = SCULLLEEYA a Rai arsine II 37, 39, 188, 189, 190, IgI, 192 —_ TELESCOPICUIN eye eyelet Il 51 = LEMELLUI tia eek etave Ser Il 46, 51, 188, 190, 192 = Eextrim epee ay ierae mores II 46, 49 . Halicornaria bipinnata............-. II 195 — campanulata........... II 72, 87, 190, 191, 193 — integra.......... ae II 83 — pluititay Ryser ects ce Il 74, 75 — ramulifera........ -.-. Il 74, 75; 195 Hebella pocillum........ 5 LL (oy avi Liyara eMyTuitiCOTNISs seer eels ree iter I 38. II 195 — Gepeehe, oo cnaspasobooocy us 1 38 LHydractinia Allmani .........+..-.- I 44 o- CAN ICAP th cre hin coe I 44, 48 = COPED Re Ok a leystans sister ee I 45 == SHO XAMDS son Crendd Heat OO oie I 44, 46. I1 187, 189, 192, 195 = PAM AB in AE Re I 45 HYDROIDA II 203 EL AP AGUEIIG! RUITEES) ee = ahs Sea she 0 oi I 44 Merona cornucopiae ..........++-.4- I 4o. II 192, 193, 195 — Michaelsent 50 vee ss I 44 Monobrachium parasiticum ......... I 42 — minuta..... Cepencta te I 48 — (POT QSIUTE sia eal Fale ss 2 I 42. Il 187, 193, 195 i ULB TOL RYDE 5222 ia\crotcisis ois I 46, 48 Monocaulus glacialis .............. I 29, 32. Il 175 — ORMGLLREN PRR. c (2 vette ears I 44 _ groenlandica.......... I 29, 33. Il 175 == SARSILM Me KAA Pehl ear ice I 44, 45, 48. 11 187, 188, _— Ata PEUALOL ey rere sees II 53, 175, 195 18g, IgI Monocoryne gigantea... . 0.0... eee en 12; 18 Hydralimania distans.........-..05: Il 137 Wigircorhelawan ctl Cauyae nina vaya 1 I9 = NELLIE tse ctsinestssterone Il 735, 188, 190, 192, 196 — (QUINT os ara Per ee DAR I 20 — Sranciscana..... Tift. eens) _ IA Ste 5 8 pO Oe See I 20 Hiybocodon Christinaé ........-+..... I 23 — PLLA EAT TO TOS I 19, 27. II 182, 183, 187, Kirchenpaueria elegans............. Il 53 189, 194, 195 — UML oy ae ste 26 not 53, 184, 190, 191, 192, Nematocarpus ramuliferus.. ccc... Il 74; 77, 190, 191, 192: 195 195 LEHREO COTO Se ORE CUO RABIES Il 7, rr 187, 189, 192, 195 Nemertesia antennina .....0... 000... II 63, 64, 67, 180, 184, SS UGA Bb Chap ED ORE oO II 9, 10, 12, 187, 188, 189, 188, 189, 190, Tg1, 192, I9I, 192, 194 195 ee PIC ALLA ree pee ale a I 173 —_ GAUL ECT a eee ia Il 63 A OMAL ELUNE oA. Nerd oP sc czcustetreatsverine II 9, 13, 34, 187, 188, 190, — TAMLOS OPN ay Pe Hae eA HE Il 63, 64, 65, 66, 190, I9I, 192, 194 IgI, 192 sen PEO TALIGISS. Pi: eye nieve ts sn, coer iss m ave: II 12, 13, 15, 189 — RESELOSUIGH A Oy EERE Il 63 en) PITT AEA: la siete toler cater ertndve eye Il 22, 24, 195 ObelaaNabella tara neem tree trer sine II 152, 167, 169 == qolite iby SeeM ea Apan omar Il 26 = fuGieilhi Zi, one tmanm nine SoBe Il 152, 166 =~ soithinien ewe Gon SeneeoeT Tier2. 03) 1459189; 191 == ihifaeSintn nase cpononoannee Il 167, 169, 170 = se SPY OM ECA eR ei acct ce s.sis Lg co; a1, 932), 345) 19L Orthopyxis caliculata.............. II 159, 160 == Syanticuae ea aneeeccnoes Il 12, 13, 15, I91 _ COmpressay. cae so sess a II 151, 159 MAY UE PE SEDs ah BASU OOO OD OOO Il 29, 30, 188, 190 — Qvertarr clase ato she Wain — . Lid bade todd DeOOeeonORe an Il 29, 195 Pachycordyle Wetsmanni............ 14 Mam pra rar CCA. ee nisis- cicceses sas 163i, 36 VTL LOSS (LY 8 BS OOO ED OE I 53. Il 187, 188, 193 = atlanticass ee. i0 te oeac ese g, Iain a5 — COT IZ Ee ee = FL 151 = SPUTpUred Eectass seer ares W Bie Be = (GONTTU CCN eB oen GOS Fe I 51 =P Rca) so eee ees Iai, 36 = PIU USCOLLES) Sit tere ch sha et ee I 52. II 195 Waormeded: (GlAGRE ~ 11s cise aieiss os» Soo Ul Zo) _ (ATTET ASR Ape bce tee I 51, 52. Il 191, 192 — CHAI a SCRA ACHE Il 164 — LON Rs AAD VOMIT O CIS I 54. Il 187, 188, 189, 193 = FELTING: Boe OAR TORE TOE 16. II 5, 151, 152, 153, Plumularia alternata............... 157 165, 166, 168,. 169, 179, (ITAA Ms 5 5 Oe GOD 6 ae II 56, 190, Ig2 190, IgI, 192, 196 -- Canlithecay i: «care e)s ce II 63, 68 = ELGIIIOS EN nhs Ao ste, tx S250 II 168, 190, 191 = (GlEWa G44 7.6 pareaoobe aco Il 57 — PETGMIALO ers taleo sorte kor 3.2 Il 165, 166, 179, 190, 191, — frIteSCEnSyas 5 tae ale, II 59, 191 192 — Semin ata vate acces alee Il 57 — FRIGHT ip Raia We Il 170, 190, 192 — sracillimans +4. .eisee st. II 69, 70, 71, 191, 195 = VCH Re Be. Se aE See Il 169, 171, 188, 190, 192 — Sroenlandicalyy, .).;.. em II 70, 71, 188, 189 — LOM ZISSIM inva er steyas 1 II 165, 166, 188, 190, 191, — plnnataraeds sai. Tl 52:53,.297 192 — PLOLiNd Aaya eet ae seve Il 60, 62 — BUT ae Be ttior Ab OteeL os aoe Il 168, 169, 170 = SCLACEI MT ASM Se. ar ee a othe Il 53; 555. 190; 192; 193; — CEC IONS 5 eG OS Gare GIs MiG II 150 195 Lictorella antipathes .. 00... .0 0. scene Il 23 — EM MTer aR teams Sel-' II 93 — nal cioideStey nie ae II 22 OGOcOnyne Cares meinc. cess ee os 145 — RENTING ESTE TB Ao sero 2, oor cusses Il 24, 25, 191 == ALS: Ac nic Secikins I 45 — GT ALTLETR PS eI CCR OER EICIS II 22, 25, 94, 188, 190, Polynemertesia gracillima ..........- Il 70, 188, 190, 191, 195 192, 195 Polyplumaria flabellata.......... . Il 59, 61, 190, I91, 193, EOUETIEIOMCUGTS Qatasois\ See sais ssleie sco 14 Il 34 195 EMECFNOFIG® PUTY GAA 6 lee ve oe wna e oe I tg. II 195 ; _ UU UULCSCENS era ciaie <6 <.si84i= II 59, 60, 190, IgI, 192 26* 204 Polyplumaria profunda BRSRS PUTA coed Il Rhizoragium roseum ............-. I Schizotricha éifurca ............ Il a QRLAPELICO erate roia)= t=) sik II Selaginopsis alternitheca........... Il — ANGH CAs eeer eee Il -— HUIS Celeeseyeterelciay sie deka aie Il = mooqOMbS. 5s aoeonase ll Sertularella amphorifera......+...-+ Il - Ehaayahutoygbet:la ga oe go oaboue ll — SESE OL TILES eee tefavet “si eleleloi=he Il — (CUB Gro oad caatngnOneos Il os pganteal ee eme nt seeemie ll — pellucida, joy emrsnt eer Il ~- POlYZOMIGS, 2. Romeesee WNL 5e So nyon ned a Fabricii hippuris Spe ath, A2ppUreS 05 itera: EV Ortigas cate teehee II 92, 195 Il 52, 53, 195 II 195 II 122 lI 101, 195 Il 115, 191, 196 Il 122 Il 1£2, 196 Il 106 Il 55, 195 Il 32, 195 Il 96 II 104 Il 122, 123, 127, 135, 188, 190, 192 Il 122, 127 Il 139, 196 II 122 II 98 Il 132, 182 II 122 Il 155 II 153, 196 T2652 ih Ay [ior 27) 365 Ib 26, 188) 190, I9I, 193, 194, 195 I 45 II Igo Il 34, 188, 193, 195 II 74, 92, 188, Ig0, I9gI, 192, 195 Il 93, 191 II 122 Il 143, 188, 190, IgI, 193 II 122, 129 II 122 II 142, 143, 146, 147 II 122 Il 148, 190, 191, 193 Il 122 Il 149 II 148 Il 122 II 141 Il 141 hi wi) II 142 HYDROIDA II 205 Thwaria inflata Toichopoma obliquum SD DO ODU RCE Don con II 122 Kkolzensisamn-nee nm ise er II 146 req ie Wan SRC OR Oe eee II 140, 142, 147, 188, 190, IgI, 192 REVEL OLLESH GRO Ts he rece ce: seule cl aihe Il 142; 143, 144, 145; 146, 190, 191 eGti tata rere ate ary (en-e II 146 MOON os ace cua ce ddor II 122 TMODUStAN n eancicrrs eis acer se II 122 Saliconuiate cps sci eis- II 120 SNe, = baa nano ooeuC dae II 122 MHompSONiine wee sc sarees =.= II 122 NL APEN Cok Crain ribs oe neta Il 739, 141, 180, 188, 190, 192, 196 ANON Peace eer eee II 122 tubulitonniise syria se ra II 132 DAMUZ ONES (ie heey rosie eek ake 3 Il 145, 190 WEES. Gclotarteeen eae maa II 122 18 SPD aS AERTS OHO II 15, 187, 188, 193, 195 Tubiclava cornucopiae............. I 4o. II 195. Tubularia Christinae Turris cornucopia....... coronata . humilis indivisa larynx obliqua prolifer pulcher Tamea . Tamosa regalis wariabilisics «esas Ty QO enon eee FO CNS Gone ZLygophylax armata......... biarmata profunda L293 M, ari I 26 I 26 6, 8, 24, 26, 30, 55- — II 187, 189, 192, 195 8, 27. II 189, 192 I 24 23 22. II 189, 190. 193 _ op IGS S327 588 20; Il 188, 192, 193, 194 I 25 39, 55- II I91 II 25 II 24, 179, 182, 183, 190, IgI, 193, 194 II 195 ERRATA. = = Part I pag. 6, line 10 stands: heteromedusoid, read: cryptomedusoid. Part II pag. 2 and following: Lafoéidae, Lafoéa, read: Lafeidae, Lafea. — Part II pag. 99, text, line 2 stands: From there is penetrates, read: From _ there it penetrates. Fig. 1. Plate I. Campanularia integra. Part of median longitudinal section showing basal part of hydranth and inner thickening of hydrotheca wall, to the upper side of which the hydranth is attached. No trace of diaphragm whatever. Specimen from Herlé, near Bergen, fixed in picrin-subli- mate-acetic acid (after Rabl), coloured with Delafield’s hamatoxyline — van Giesson. 320/1. Branchiocerianthus rentformis. Type specimen from “Ingolf’ St. 28. Nat. size. Branchiocertanthus reniformis. Wydranth seen from below. 2/1. Branchiocerianthus reniformts. Wydranth seen from above. The richly folded gastral endoderm distinctly visible through the large oral aperture. 2/1. Branchiocerianthus reniformts. Primary branch of a blastostyle, showing method of ramifica- tion. The outer, grape-like swellings are close collections of quite small incipient gonophores. 30/1 The Ingolf Expedition, V, 7. Hj. Broch del. et phot. Broch: Hydroida. Plate I. Ljustr. A. B. Lagrelius & Westphal, Stockholm ree NGO EXPEDITION S95 SOG, THE LOCALITIES, DEPTHS, AND BOTTOMTEMPERATURES OF THE STATIONS Depth Depth | Depth | Station eee | |hene. Ww. | in Bottom-) Station seh Ry, | OBS PEAAWE in Bottom-| Station Tacince| tone! wel in | Bottom- Nr. | Danish | temp. Nr. : Danish temp. Nr. _Danish _ temp. fathomis | fathoms ‘fathoms | 7 = aay lia Saas =a 7 aia i i. oF Seamer a) [aaa Th ; ie — 7 = I 62° 30! Sosa 132 722 24 63° 06’ 56° 00 I1g99 2°4 | 45 6r° 32 9° 43° 643 | 4°17 2 63° 04’ 9° 22’ 262 5°3 25 6250; ||) 54° 255; 582 393 46 61s! T2236 720 2°40 | 3 63° 35° | 10° 24! 272 0°5 OBES | 53m 03) 136 47 61° 32" | 13°40 950 | 3°23 Ao) 64°07" Roy t2 237 2°5 26 Gg ose 52° air! 34 0°6 48 61° 32 15° 00 1150 ac, 5 64° 4o' 12° 09' 155 64° 37’ 54° 24’ 109 | 49 62° 07 15° 07" 1120 2°91 6 63° 43" 14° 34’ go 7°0 27 64° 54’ 55° Lor 393 3°8 || 50 62° 43 15° 07" 1020 aon: 7 63° 73% 15° 41 600 4°5 28 65° 14 55° 42’ 420 3°5 51 64° 15 ny BI 68 7032 8 63° 56° 24° 40" 136 6°0 29 65° 34° 54° 31 68 O22 Ie a s2 63° 57 132 32 420 7°87 9 64°18" | 27° 00; 295 SOO 66° 50’ | 54° 28" 22 1°05 | 53 63° 15 15° 07 795 3°08 10 64° 24° | 28° 50 788 3°5 | 3x | 66°35’ | 55°54’ 88 1°6 54 63° 08' | 15° 40 691 3°9 II 64° 34° SORT On 1300 1°6 32 66° 35’ | 56° 38 318 3°9 55 63° 33’ T5° 02’ 316 5°9 12 64° 38° | 32° 37 1040 0°3 33 i SU || ES eo 35 0°8 56 64° 00’ | 15° 09! 68 ial 13 =H 64° 47' | 34° 33° 622 3°0 34 Ce ay 3 Gulag) 55 | 57 63° 37 13° 02 350 3°4 14 | 64°45’ | 35% 05 176 4°4 35 G5 CenOm tS 5.05 362 3°6 58 64° 25 12° 09! 211 0°S 15 | 66° 18’ | 25° 59 330 —0°75 36 61° 50 56° 21’ 1435 mos 59 65° 00 LEG! 310 |—o°r 16 65° 43/ | 26° 58’ 250 6° || 37 60° 17° | 54° 05’ 1715 1°4 | 60 65° 09' T2027" 124 0°9 WW )| 922749) 9) 269155: 745 3°4 38 59u tai Mesto O5.0\(5 1870 woe |) Gi 65° 03’ 13° 06" Gy | 9 Re 18 61° 44’ | 30° 20/ 1135 3°0 39 =| 62°00’ | 22° 38’ 865 2°9 62 63218! | x9° 12’ 72 7°92 19 | 60°29' | 34° 14’ 1566 2°4 || 40 G2°'00) 27.9136" 845) 393) || 63 62° 40’ | 19° 05’ 800 4°o 20 58° 20' 40° 48’ 1695 Les 41 61° 39 17° to 1245 | 2°o | 64 62° 06' 19° 00 1041 Ber 21 58° or | 44° 45' 1330 2°4 || 42 61°40" |) 10° 17’ 625 | 0% | 65 619 33% 19° 00’ 1089 3°0 22 58° 10’ 48° 25’ 1845 1°4 | 43 61° 42’ | LOS ET! 645 0°05 66 61° 33 20° 43 1128 ste 23 | 60° 43° | 56° 00’ | Piankton-Xe | 44 61° 42’ | 9° 36’ 545 | 4°8 67 61° 30’ | 22° 30 975 3°0 used Depth Depth | | Depth | Station TAN | onewe in. Bottom- | Station Lat. N. |Long. W. in ‘Bottom-) Station Tat. N. |Long. W in | Bottom- Nr. Danish — temp. Nr. Danish | temp. | Nr. | | Danish | temp. fathoms | | fathoms | | | | fathoms 68 62° 06' 22° 30' 843 3°4 92 64° 44’ 3200521 976 1°4 || 118 68° 27’ 8° 20’ 1060 | —I1°o 69 62° 40’ 2205 7s | 589 3°9 93 64° 24’ | Age awl! 767 | 1°46 Tig | 67°53' 10° 19’ 1o1o | —I°o 7O 63° 09! 22° 05' 134 7°0 94 64° 56' 36° 109’ 204 | Acar 120 67° 29’ Tho 2 885 | —1°o 71 | 63° 46' 22° 03° 46 OS ones oce se 213 12t | 66°50! iegye aria 529 —0°7 72 63°12’ | 23° 04’ 197 627 95 65° 14’ | 30° 39 752 | 2ON 122 | 66° 42' 14° 44’ | 115 | 1°8 | | 73 62° 58' | 23° 28’ 486 55 96 65° 24’ | 29° 00’ | Tee) Ti) 123 66° 52’ | 15° 40° 145 2°o 74 | 62017’ | 24°36’ | 695 | 4°2 || 97 | 65°28’ | 27%39/ | 450 | 5°5 | 124 | 67° 40° | 15°40’ 495 | —0°6 619 57) |) 250135) | 761 | | 98 65° 38’ | 26007 | 138 5°9 125 68° 08’ 16° 02° 729 | —0°8 61° 28’ | 25° 06' 829 | | 99 66° 13/ | 25053" | 187 6°r 126 | GP rusy || 15° 52’ 293 | —0°5 75 61° 28’ | 26° 25° 780 4°3 || 00 66°. 23’ 14° 02’ | 59 | 0° 4 127 ai) 662.23 fF 208705; 44 5°6 76 60° 50 26° 50 806 4° | 101 66° 23’ 12° 05 537. | —0°7 128 | 66° 50’ | 20° 02' 194 0°6 77 60° 10 26° 59° | 951 3°6 | 102 66° 23' | 10? 26' | 750 | —o°9 129 | 66° 35) | 23°47’ 117 6°5 78 60° 37 yp 03 799 4°5 103 66° 23’ | g° 52’ | 57h | = oc6 130 | 63°00’ | 20°40! 338 | 6°55 79 60° 52" 28° 58’ 653 | 4°4 104 66° 23! Foe se 957 | —J°T 131 | 63° 00° | T9° 09’ | 698 | 4°7 So 61° 02’ 29° 32’ 935 4°0 105 65° 34’ aie 762 —o°S 132 63° 00' | L704" 747 4°6 Si 61° 44’ 27° 00 485 6°r | 106 65234") eSisat 447 —0°6 TASH OSUnTA. | 11° 24' | 230 222 82 Gms Sian Aree 824 4°r |i 65° 20' 8° 4o’ 466 134 62° 34’ 10° 26’ 299 AST 83 | 62° 25 28° 30 gi2 205 107 65° 33) 10° 28 492 0°3 135 | 62° 48’ 9° 48’ 270 0°4 62° 36 26° or’ 472 | 108 65° 30° | T2900! 97 Tie 136 | 63° o1’ g° 11 256 4°8 62° 36 25° 30° 401 109 65°20’ | 13°25’ 38 Gels 133 7 os ouat| | Sar’ 297 | —0°%6 S4 | 62° 58’ 25° 24' 633 | 4°8 || I10 | 66244" | Tres’ 781 0°88 | 1:3 9) a 0G Sho 61 5) 7 245 Oa meee ra —0°6 85 63° 21’ 252 oT ee l7zO | II 67° 14’ 8° 48 S60 0°9 139 | 637 36 7230) 702 —o0°6 | 86 65° 03'6 | 23° 476 | 76 | 112 G7 SIS7 Ue Goran | 1267 | —1°%r | T4o || (63° 201 6° 57’ 780 | —0°9 87 | 65°02’; | 23° 56’2 Io | 113 69° 31’ 7° 06’ | 1309 —120)))||) erg, 63220" 6° 58’ 679 —0°6 88 | 64° 58’ 24° 2'5" 76 6°9 114 70° 36' | F229) 773 1°20 || 142 | 63° 07’ 7elont 587 —o0°6 89 64° 45’ | 27° 20 310 | 894 | 275 70° 50 | 8° 20! 86 O°! 143 62°58 3) 7°"09 388 | —o0%4 90 64° 45' 29° 06' 568 4°4 116 70° 05’ 8° 26’ 371 —o°4 || 144 | 62° 49’ 7 Tos 276 1°6 gl 64° 44’ 31°.00' 1236 aon 117 69° 13' Sora | 1003, 1°0 | | | | | Ree + kg ( MORO>F PYL YO AAPM UIDM PUD PP} OI UPIMVIG PLANT | PUDSPUNT PULEOS bo PLOY Uap PUL arUrpasuarsy) ~ ~~~ ~~ jnoep ii O00T\ aro e008 00L O0L 009 009 oor 008 Oor > (Suloyzos Ystupp ) ausm Taysupp oot oO fe 09 ; | V2)4shp | hurr SS a ee: aT? ; 09 (M012 1)\ 7 So 009 of9 | ’ : ‘9681 ¥ C681 UuorMtpedxy jposuy ie iP tine | aT i | ||} i | | } Hil || | wie 7453"